Installation und Konfigurationsdateien von Postfix unter CentOS 7.x

Bild: Postfix-Logo
Nachdem wir uns einen grundlegenden Überblick über Postfix verschafft haben, werden wir uns nun eingehend mit der Installation und Grundkonfiguration unseres Postfix-MTA1) beschäftigen.

Seit CentOS 6.0 wird als MTA Postfix installiert - aktuell ist dies der 2.10er Release. Falls bereits nicht bei der Grundinstallation unseres Hosts automatisch der MTA installiert wurde, holen wir diesen Schritt mit Hilfe von yum einfach nach.

 # yum install postfix -y

Was uns das RPM-Paket alles mitgebracht hat, erkunden wir bei Bedarf mit Hilfe des Befehls rpm -qil.

 # rpm -qil
Name        : postfix
Epoch       : 2
Version     : 2.10.1
Release     : 6.el7
Architecture: x86_64
Install Date: Sun 28 Sep 2014 09:04:39 PM CEST
Group       : System Environment/Daemons
Size        : 12773475
License     : IBM and GPLv2+
Signature   : RSA/SHA256, Fri 04 Jul 2014 06:33:15 AM CEST, Key ID 24c6a8a7f4a80eb5
Source RPM  : postfix-2.10.1-6.el7.src.rpm
Build Date  : Tue 10 Jun 2014 03:39:36 AM CEST
Build Host  : worker1.bsys.centos.org
Relocations : (not relocatable)
Packager    : CentOS BuildSystem <http://bugs.centos.org>
Vendor      : CentOS
URL         : http://www.postfix.org
Summary     : Postfix Mail Transport Agent
Description :
Postfix is a Mail Transport Agent (MTA), supporting LDAP, SMTP AUTH (SASL),
TLS
/etc/pam.d/smtp
/etc/pam.d/smtp.postfix
/etc/postfix
/etc/postfix/access
/etc/postfix/canonical
/etc/postfix/generic
/etc/postfix/header_checks
/etc/postfix/main.cf
/etc/postfix/master.cf
/etc/postfix/relocated
/etc/postfix/transport
/etc/postfix/virtual
/etc/sasl2/smtpd.conf
/usr/bin/mailq
/usr/bin/mailq.postfix
/usr/bin/newaliases
/usr/bin/newaliases.postfix
/usr/bin/rmail
/usr/bin/rmail.postfix
/usr/lib/sendmail
/usr/lib/sendmail.postfix
/usr/lib/systemd/system/postfix.service
/usr/libexec/postfix
/usr/libexec/postfix/aliasesdb
/usr/libexec/postfix/anvil
/usr/libexec/postfix/bounce
/usr/libexec/postfix/chroot-update
/usr/libexec/postfix/cleanup
/usr/libexec/postfix/discard
/usr/libexec/postfix/dnsblog
/usr/libexec/postfix/error
/usr/libexec/postfix/flush
/usr/libexec/postfix/lmtp
/usr/libexec/postfix/local
/usr/libexec/postfix/main.cf
/usr/libexec/postfix/master
/usr/libexec/postfix/master.cf
/usr/libexec/postfix/nqmgr
/usr/libexec/postfix/oqmgr
/usr/libexec/postfix/pickup
/usr/libexec/postfix/pipe
/usr/libexec/postfix/post-install
/usr/libexec/postfix/postfix-files
/usr/libexec/postfix/postfix-script
/usr/libexec/postfix/postfix-wrapper
/usr/libexec/postfix/postmulti-script
/usr/libexec/postfix/postscreen
/usr/libexec/postfix/proxymap
/usr/libexec/postfix/qmgr
/usr/libexec/postfix/qmqpd
/usr/libexec/postfix/scache
/usr/libexec/postfix/showq
/usr/libexec/postfix/smtp
/usr/libexec/postfix/smtpd
/usr/libexec/postfix/spawn
/usr/libexec/postfix/tlsmgr
/usr/libexec/postfix/tlsproxy
/usr/libexec/postfix/trivial-rewrite
/usr/libexec/postfix/verify
/usr/libexec/postfix/virtual
/usr/sbin/postalias
/usr/sbin/postcat
/usr/sbin/postconf
/usr/sbin/postdrop
/usr/sbin/postfix
/usr/sbin/postkick
/usr/sbin/postlock
/usr/sbin/postlog
/usr/sbin/postmap
/usr/sbin/postmulti
/usr/sbin/postqueue
/usr/sbin/postsuper
/usr/sbin/sendmail
/usr/sbin/sendmail.postfix
/usr/sbin/smtp-sink
/usr/sbin/smtp-source
/usr/share/doc/postfix-2.10.1
/usr/share/doc/postfix-2.10.1/COMPATIBILITY
/usr/share/doc/postfix-2.10.1/LICENSE
/usr/share/doc/postfix-2.10.1/README-Postfix-SASL-RedHat.txt
/usr/share/doc/postfix-2.10.1/README_FILES
/usr/share/doc/postfix-2.10.1/README_FILES/AAAREADME
/usr/share/doc/postfix-2.10.1/README_FILES/ADDRESS_CLASS_README
/usr/share/doc/postfix-2.10.1/README_FILES/ADDRESS_REWRITING_README
/usr/share/doc/postfix-2.10.1/README_FILES/ADDRESS_VERIFICATION_README
/usr/share/doc/postfix-2.10.1/README_FILES/BACKSCATTER_README
/usr/share/doc/postfix-2.10.1/README_FILES/BASIC_CONFIGURATION_README
/usr/share/doc/postfix-2.10.1/README_FILES/BUILTIN_FILTER_README
/usr/share/doc/postfix-2.10.1/README_FILES/CDB_README
/usr/share/doc/postfix-2.10.1/README_FILES/CONNECTION_CACHE_README
/usr/share/doc/postfix-2.10.1/README_FILES/CONTENT_INSPECTION_README
/usr/share/doc/postfix-2.10.1/README_FILES/DATABASE_README
/usr/share/doc/postfix-2.10.1/README_FILES/DB_README
/usr/share/doc/postfix-2.10.1/README_FILES/DEBUG_README
/usr/share/doc/postfix-2.10.1/README_FILES/DSN_README
/usr/share/doc/postfix-2.10.1/README_FILES/ETRN_README
/usr/share/doc/postfix-2.10.1/README_FILES/FILTER_README
/usr/share/doc/postfix-2.10.1/README_FILES/INSTALL
/usr/share/doc/postfix-2.10.1/README_FILES/IPV6_README
/usr/share/doc/postfix-2.10.1/README_FILES/LDAP_README
/usr/share/doc/postfix-2.10.1/README_FILES/LINUX_README
/usr/share/doc/postfix-2.10.1/README_FILES/LOCAL_RECIPIENT_README
/usr/share/doc/postfix-2.10.1/README_FILES/MAILDROP_README
/usr/share/doc/postfix-2.10.1/README_FILES/MEMCACHE_README
/usr/share/doc/postfix-2.10.1/README_FILES/MILTER_README
/usr/share/doc/postfix-2.10.1/README_FILES/MULTI_INSTANCE_README
/usr/share/doc/postfix-2.10.1/README_FILES/MYSQL_README
/usr/share/doc/postfix-2.10.1/README_FILES/NFS_README
/usr/share/doc/postfix-2.10.1/README_FILES/OVERVIEW
/usr/share/doc/postfix-2.10.1/README_FILES/PACKAGE_README
/usr/share/doc/postfix-2.10.1/README_FILES/PCRE_README
/usr/share/doc/postfix-2.10.1/README_FILES/PGSQL_README
/usr/share/doc/postfix-2.10.1/README_FILES/POSTSCREEN_README
/usr/share/doc/postfix-2.10.1/README_FILES/QSHAPE_README
/usr/share/doc/postfix-2.10.1/README_FILES/RELEASE_NOTES
/usr/share/doc/postfix-2.10.1/README_FILES/RESTRICTION_CLASS_README
/usr/share/doc/postfix-2.10.1/README_FILES/SASL_README
/usr/share/doc/postfix-2.10.1/README_FILES/SCHEDULER_README
/usr/share/doc/postfix-2.10.1/README_FILES/SMTPD_ACCESS_README
/usr/share/doc/postfix-2.10.1/README_FILES/SMTPD_POLICY_README
/usr/share/doc/postfix-2.10.1/README_FILES/SMTPD_PROXY_README
/usr/share/doc/postfix-2.10.1/README_FILES/SOHO_README
/usr/share/doc/postfix-2.10.1/README_FILES/SQLITE_README
/usr/share/doc/postfix-2.10.1/README_FILES/STANDARD_CONFIGURATION_README
/usr/share/doc/postfix-2.10.1/README_FILES/STRESS_README
/usr/share/doc/postfix-2.10.1/README_FILES/TLS_LEGACY_README
/usr/share/doc/postfix-2.10.1/README_FILES/TLS_README
/usr/share/doc/postfix-2.10.1/README_FILES/TUNING_README
/usr/share/doc/postfix-2.10.1/README_FILES/ULTRIX_README
/usr/share/doc/postfix-2.10.1/README_FILES/UUCP_README
/usr/share/doc/postfix-2.10.1/README_FILES/VERP_README
/usr/share/doc/postfix-2.10.1/README_FILES/VIRTUAL_README
/usr/share/doc/postfix-2.10.1/README_FILES/XCLIENT_README
/usr/share/doc/postfix-2.10.1/README_FILES/XFORWARD_README
/usr/share/doc/postfix-2.10.1/TLS_ACKNOWLEDGEMENTS
/usr/share/doc/postfix-2.10.1/TLS_LICENSE
/usr/share/doc/postfix-2.10.1/bounce.cf.default
/usr/share/doc/postfix-2.10.1/examples
/usr/share/doc/postfix-2.10.1/examples/chroot-setup
/usr/share/doc/postfix-2.10.1/examples/chroot-setup/LINUX2
/usr/share/doc/postfix-2.10.1/examples/qmail-local
/usr/share/doc/postfix-2.10.1/examples/qmail-local/qmail-local.txt
/usr/share/doc/postfix-2.10.1/examples/smtpd-policy
/usr/share/doc/postfix-2.10.1/examples/smtpd-policy/README.SPF
/usr/share/doc/postfix-2.10.1/examples/smtpd-policy/greylist.pl
/usr/share/doc/postfix-2.10.1/main.cf.default
/usr/share/man/man1/mailq.1.gz
/usr/share/man/man1/mailq.postfix.1.gz
/usr/share/man/man1/newaliases.1.gz
/usr/share/man/man1/newaliases.postfix.1.gz
/usr/share/man/man1/postalias.1.gz
/usr/share/man/man1/postcat.1.gz
/usr/share/man/man1/postconf.1.gz
/usr/share/man/man1/postdrop.1.gz
/usr/share/man/man1/postfix.1.gz
/usr/share/man/man1/postkick.1.gz
/usr/share/man/man1/postlock.1.gz
/usr/share/man/man1/postlog.1.gz
/usr/share/man/man1/postmap.1.gz
/usr/share/man/man1/postmulti.1.gz
/usr/share/man/man1/postqueue.1.gz
/usr/share/man/man1/postsuper.1.gz
/usr/share/man/man1/sendmail.postfix.1.gz
/usr/share/man/man1/smtp-sink.1.gz
/usr/share/man/man1/smtp-source.1.gz
/usr/share/man/man5/access.5.gz
/usr/share/man/man5/aliases.5.gz
/usr/share/man/man5/aliases.postfix.5.gz
/usr/share/man/man5/body_checks.5.gz
/usr/share/man/man5/bounce.5.gz
/usr/share/man/man5/canonical.5.gz
/usr/share/man/man5/cidr_table.5.gz
/usr/share/man/man5/generic.5.gz
/usr/share/man/man5/header_checks.5.gz
/usr/share/man/man5/ldap_table.5.gz
/usr/share/man/man5/master.5.gz
/usr/share/man/man5/memcache_table.5.gz
/usr/share/man/man5/mysql_table.5.gz
/usr/share/man/man5/nisplus_table.5.gz
/usr/share/man/man5/pcre_table.5.gz
/usr/share/man/man5/pgsql_table.5.gz
/usr/share/man/man5/postconf.5.gz
/usr/share/man/man5/postfix-wrapper.5.gz
/usr/share/man/man5/regexp_table.5.gz
/usr/share/man/man5/relocated.5.gz
/usr/share/man/man5/sqlite_table.5.gz
/usr/share/man/man5/tcp_table.5.gz
/usr/share/man/man5/transport.5.gz
/usr/share/man/man5/virtual.5.gz
/usr/share/man/man8/anvil.8.gz
/usr/share/man/man8/bounce.8.gz
/usr/share/man/man8/cleanup.8.gz
/usr/share/man/man8/defer.8.gz
/usr/share/man/man8/discard.8.gz
/usr/share/man/man8/dnsblog.8.gz
/usr/share/man/man8/error.8.gz
/usr/share/man/man8/flush.8.gz
/usr/share/man/man8/lmtp.8.gz
/usr/share/man/man8/local.8.gz
/usr/share/man/man8/master.8.gz
/usr/share/man/man8/oqmgr.8.gz
/usr/share/man/man8/pickup.8.gz
/usr/share/man/man8/pipe.8.gz
/usr/share/man/man8/postscreen.8.gz
/usr/share/man/man8/proxymap.8.gz
/usr/share/man/man8/qmgr.8.gz
/usr/share/man/man8/qmqpd.8.gz
/usr/share/man/man8/scache.8.gz
/usr/share/man/man8/sendmail.8.gz
/usr/share/man/man8/showq.8.gz
/usr/share/man/man8/smtp.8.gz
/usr/share/man/man8/smtpd.8.gz
/usr/share/man/man8/spawn.8.gz
/usr/share/man/man8/tlsmgr.8.gz
/usr/share/man/man8/tlsproxy.8.gz
/usr/share/man/man8/trace.8.gz
/usr/share/man/man8/trivial-rewrite.8.gz
/usr/share/man/man8/verify.8.gz
/usr/share/man/man8/virtual.8.gz
/var/lib/misc/postfix.aliasesdb-stamp
/var/lib/postfix
/var/spool/postfix
/var/spool/postfix/active
/var/spool/postfix/bounce
/var/spool/postfix/corrupt
/var/spool/postfix/defer
/var/spool/postfix/deferred
/var/spool/postfix/flush
/var/spool/postfix/hold
/var/spool/postfix/incoming
/var/spool/postfix/maildrop
/var/spool/postfix/pid
/var/spool/postfix/private
/var/spool/postfix/public
/var/spool/postfix/saved
/var/spool/postfix/trace

Mit dem Netzwerkprotokoll DANE2) kann die Kommunikation mit anderen MTAs weiter abgesichert werden. Die X.509-Zertifikate für die Transportverschlüsselung werden dabei mit DNS-Einträgen verknüpft und sind somit per DNSSEC3) sicher abgesichert. Dieses neue Sicherheitsfeature steht ab Postfix Version 2.11 zur Verfügung.

Die entsprechenden Pakete für die Installation von Postfix 2.11 nehmen wir am einfachsten wieder mit Hilfe von yum vor - Voraussetzung man hat sich das Paket vom Repository mailserver.guru heruntergeladen.

 # yum localinstall http://repo.mailserver.guru/7/os/x86_64/Packages/postfix-2.11.6-1.el7.centos.x86_64.rpm

Einfacher geht es natürlich, wenn das Repository mailserver.guru eingebunden hat. Dann reicht der gewohnte Aufruf von yum.

 # yum install postfix -y

Was uns das RPM-Paket alles mitgebracht hat, erkunden wir bei Bedarf mit Hilfe des Befehls rpm -qil.

 # rpm -qil postfix
Name        : postfix                                                                                                                                                              
Epoch       : 2                                                                                                                                                                    
Version     : 2.11.6                                                                                                                                                               
Release     : 1.el7.centos                                                                                                                                                         
Architecture: x86_64                                                                                                                                                               
Install Date: Wed 07 Oct 2015 09:43:33 AM CEST                                                                                                                                     
Group       : System Environment/Daemons                                                                                                                                           
Size        : 13027820                                                                                                                                                             
License     : IBM and GPLv2+                                                                                                                                                       
Signature   : RSA/SHA1, Wed 07 Oct 2015 09:38:48 AM CEST, Key ID 60ecfb9e8195aea0                                                                                                  
Source RPM  : postfix-2.11.6-1.el7.centos.src.rpm                                                                                                                                  
Build Date  : Wed 07 Oct 2015 09:38:24 AM CEST                                                                                                                                     
Build Host  : vml000200.dmz.nausch.org                                                                                                                                             
Relocations : (not relocatable)                                                                                                                                                    
Packager    : Django <django@mailserver.guru>                                                                                                                                      
Vendor      : Django                                                                                                                                                               
URL         : http://www.postfix.org                                                                                                                                               
Summary     : Postfix Mail Transport Agent                                                                                                                                         
Description :                                                                                                                                                                      
Postfix is a Mail Transport Agent (MTA), supporting LDAP, SMTP AUTH (SASL),                                                                                                        
TLS                                                                                                                                                                                
/etc/pam.d/smtp                                                                                                                                                                    
/etc/pam.d/smtp.postfix                                                                                                                                                            
/etc/postfix                                                                                                                                                                       
/etc/postfix/access                                                                                                                                                                
/etc/postfix/canonical                                                                                                                                                             
/etc/postfix/generic                                                                                                                                                               
/etc/postfix/header_checks                                                                                                                                                         
/etc/postfix/main.cf                                                                                                                                                               
/etc/postfix/master.cf                                                                                                                                                             
/etc/postfix/relocated                                                                                                                                                             
/etc/postfix/transport                                                                                                                                                             
/etc/postfix/virtual                                                                                                                                                               
/etc/sasl2/smtpd.conf                                                                                                                                                              
/usr/bin/mailq                                                                                                                                                                     
/usr/bin/mailq.postfix                                                                                                                                                             
/usr/bin/newaliases                                                                                                                                                                
/usr/bin/newaliases.postfix                                                                                                                                                        
/usr/bin/rmail                                                                                                                                                                     
/usr/bin/rmail.postfix                                                                                                                                                             
/usr/lib/sendmail                                                                                                                                                                  
/usr/lib/sendmail.postfix                                                                                                                                                          
/usr/lib/systemd/system/postfix.service                                                                                                                                            
/usr/libexec/postfix                                                                                                                                                               
/usr/libexec/postfix/aliasesdb                                                                                                                                                     
/usr/libexec/postfix/anvil                                                                                                                                                         
/usr/libexec/postfix/bounce                                                                                                                                                        
/usr/libexec/postfix/chroot-update                                                                                                                                                 
/usr/libexec/postfix/cleanup                                                                                                                                                       
/usr/libexec/postfix/discard                                                                                                                                                       
/usr/libexec/postfix/dnsblog                                                                                                                                                       
/usr/libexec/postfix/error                                                                                                                                                         
/usr/libexec/postfix/flush                                                                                                                                                         
/usr/libexec/postfix/lmtp                                                                                                                                                          
/usr/libexec/postfix/local                                                                                                                                                         
/usr/libexec/postfix/main.cf                                                                                                                                                       
/usr/libexec/postfix/master                                                                                                                                                        
/usr/libexec/postfix/master.cf                                                                                                                                                     
/usr/libexec/postfix/nqmgr                                                                                                                                                         
/usr/libexec/postfix/oqmgr                                                                                                                                                         
/usr/libexec/postfix/pickup                                                                                                                                                        
/usr/libexec/postfix/pipe                                                                                                                                                          
/usr/libexec/postfix/post-install                                                                                                                                                  
/usr/libexec/postfix/postfix-files                                                                                                                                                 
/usr/libexec/postfix/postfix-script                                                                                                                                                
/usr/libexec/postfix/postfix-wrapper                                                                                                                                               
/usr/libexec/postfix/postmulti-script                                                                                                                                              
/usr/libexec/postfix/postscreen                                                                                                                                                    
/usr/libexec/postfix/proxymap                                                                                                                                                      
/usr/libexec/postfix/qmgr                                                                                                                                                          
/usr/libexec/postfix/qmqpd                                                                                                                                                         
/usr/libexec/postfix/scache                                                                                                                                                        
/usr/libexec/postfix/showq                                                                                                                                                         
/usr/libexec/postfix/smtp                                                                                                                                                          
/usr/libexec/postfix/smtpd                                                                                                                                                         
/usr/libexec/postfix/spawn                                                                                                                                                         
/usr/libexec/postfix/tlsmgr                                                                                                                                                        
/usr/libexec/postfix/tlsproxy                                                                                                                                                      
/usr/libexec/postfix/trivial-rewrite                                                                                                                                               
/usr/libexec/postfix/verify                                                                                                                                                        
/usr/libexec/postfix/virtual                                                                                                                                                       
/usr/sbin/postalias                                                                                                                                                                
/usr/sbin/postcat                                                                                                                                                                  
/usr/sbin/postconf                                                                                                                                                                 
/usr/sbin/postdrop                                                                                                                                                                 
/usr/sbin/postfix                                                                                                                                                                  
/usr/sbin/postkick                                                                                                                                                                 
/usr/sbin/postlock                                                                                                                                                                 
/usr/sbin/postlog                                                                                                                                                                  
/usr/sbin/postmap                                                                                                                                                                  
/usr/sbin/postmulti                                                                                                                                                                
/usr/sbin/postqueue                                                                                                                                                                
/usr/sbin/postsuper                                                                                                                                                                
/usr/sbin/sendmail                                                                                                                                                                 
/usr/sbin/sendmail.postfix                                                                                                                                                         
/usr/sbin/smtp-sink                                                                                                                                                                
/usr/sbin/smtp-source                                                                                                                                                              
/usr/share/doc/postfix-2.11.6                                                                                                                                                      
/usr/share/doc/postfix-2.11.6/COMPATIBILITY                                                                                                                                        
/usr/share/doc/postfix-2.11.6/LICENSE                                                                                                                                              
/usr/share/doc/postfix-2.11.6/README-Postfix-SASL-RedHat.txt                                                                                                                       
/usr/share/doc/postfix-2.11.6/README_FILES                                                                                                                                         
/usr/share/doc/postfix-2.11.6/README_FILES/AAAREADME                                                                                                                               
/usr/share/doc/postfix-2.11.6/README_FILES/ADDRESS_CLASS_README                                                                                                                    
/usr/share/doc/postfix-2.11.6/README_FILES/ADDRESS_REWRITING_README                                                                                                                
/usr/share/doc/postfix-2.11.6/README_FILES/ADDRESS_VERIFICATION_README                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/BACKSCATTER_README                                                                                                                      
/usr/share/doc/postfix-2.11.6/README_FILES/BASIC_CONFIGURATION_README                                                                                                              
/usr/share/doc/postfix-2.11.6/README_FILES/BUILTIN_FILTER_README                                                                                                                   
/usr/share/doc/postfix-2.11.6/README_FILES/CDB_README                                                                                                                              
/usr/share/doc/postfix-2.11.6/README_FILES/CONNECTION_CACHE_README                                                                                                                 
/usr/share/doc/postfix-2.11.6/README_FILES/CONTENT_INSPECTION_README                                                                                                               
/usr/share/doc/postfix-2.11.6/README_FILES/DATABASE_README                                                                                                                         
/usr/share/doc/postfix-2.11.6/README_FILES/DB_README                                                                                                                               
/usr/share/doc/postfix-2.11.6/README_FILES/DEBUG_README                                                                                                                            
/usr/share/doc/postfix-2.11.6/README_FILES/DSN_README                                                                                                                              
/usr/share/doc/postfix-2.11.6/README_FILES/ETRN_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/FILTER_README                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/FORWARD_SECRECY_README                                                                                                                  
/usr/share/doc/postfix-2.11.6/README_FILES/INSTALL                                                                                                                                 
/usr/share/doc/postfix-2.11.6/README_FILES/IPV6_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/LDAP_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/LINUX_README                                                                                                                            
/usr/share/doc/postfix-2.11.6/README_FILES/LMDB_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/LOCAL_RECIPIENT_README                                                                                                                  
/usr/share/doc/postfix-2.11.6/README_FILES/MAILDROP_README                                                                                                                         
/usr/share/doc/postfix-2.11.6/README_FILES/MEMCACHE_README                                                                                                                         
/usr/share/doc/postfix-2.11.6/README_FILES/MILTER_README                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/MULTI_INSTANCE_README                                                                                                                   
/usr/share/doc/postfix-2.11.6/README_FILES/MYSQL_README                                                                                                                            
/usr/share/doc/postfix-2.11.6/README_FILES/NFS_README                                                                                                                              
/usr/share/doc/postfix-2.11.6/README_FILES/OVERVIEW                                                                                                                                
/usr/share/doc/postfix-2.11.6/README_FILES/PACKAGE_README                                                                                                                          
/usr/share/doc/postfix-2.11.6/README_FILES/PCRE_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/PGSQL_README                                                                                                                            
/usr/share/doc/postfix-2.11.6/README_FILES/POSTSCREEN_README                                                                                                                       
/usr/share/doc/postfix-2.11.6/README_FILES/QSHAPE_README                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/RELEASE_NOTES                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/RESTRICTION_CLASS_README                                                                                                                
/usr/share/doc/postfix-2.11.6/README_FILES/SASL_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/SCHEDULER_README                                                                                                                        
/usr/share/doc/postfix-2.11.6/README_FILES/SMTPD_ACCESS_README                                                                                                                     
/usr/share/doc/postfix-2.11.6/README_FILES/SMTPD_POLICY_README                                                                                                                     
/usr/share/doc/postfix-2.11.6/README_FILES/SMTPD_PROXY_README                                                                                                                      
/usr/share/doc/postfix-2.11.6/README_FILES/SOHO_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/SQLITE_README                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/STANDARD_CONFIGURATION_README                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/STRESS_README                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/TLS_LEGACY_README                                                                                                                       
/usr/share/doc/postfix-2.11.6/README_FILES/TLS_README                                                                                                                              
/usr/share/doc/postfix-2.11.6/README_FILES/TUNING_README                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/ULTRIX_README                                                                                                                           
/usr/share/doc/postfix-2.11.6/README_FILES/UUCP_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/VERP_README                                                                                                                             
/usr/share/doc/postfix-2.11.6/README_FILES/VIRTUAL_README                                                                                                                          
/usr/share/doc/postfix-2.11.6/README_FILES/XCLIENT_README                                                                                                                          
/usr/share/doc/postfix-2.11.6/README_FILES/XFORWARD_README                                                                                                                         
/usr/share/doc/postfix-2.11.6/TLS_ACKNOWLEDGEMENTS                                                                                                                                 
/usr/share/doc/postfix-2.11.6/TLS_LICENSE                                                                                                                                          
/usr/share/doc/postfix-2.11.6/bounce.cf.default                                                                                                                                    
/usr/share/doc/postfix-2.11.6/examples                                                                                                                                             
/usr/share/doc/postfix-2.11.6/examples/chroot-setup                                                                                                                                
/usr/share/doc/postfix-2.11.6/examples/chroot-setup/LINUX2                                                                                                                         
/usr/share/doc/postfix-2.11.6/examples/qmail-local                                                                                                                                 
/usr/share/doc/postfix-2.11.6/examples/qmail-local/qmail-local.txt                                                                                                                 
/usr/share/doc/postfix-2.11.6/examples/smtpd-policy                                                                                                                                
/usr/share/doc/postfix-2.11.6/examples/smtpd-policy/README.SPF                                                                                                                     
/usr/share/doc/postfix-2.11.6/examples/smtpd-policy/greylist.pl                                                                                                                    
/usr/share/doc/postfix-2.11.6/main.cf.default                                                                                                                                      
/usr/share/man/man1/mailq.1.gz                                                                                                                                                     
/usr/share/man/man1/mailq.postfix.1.gz                                                                                                                                             
/usr/share/man/man1/newaliases.1.gz                                                                                                                                                
/usr/share/man/man1/newaliases.postfix.1.gz                                                                                                                                        
/usr/share/man/man1/postalias.1.gz                                                                                                                                                 
/usr/share/man/man1/postcat.1.gz                                                                                                                                                   
/usr/share/man/man1/postconf.1.gz                                                                                                                                                  
/usr/share/man/man1/postdrop.1.gz                                                                                                                                                  
/usr/share/man/man1/postfix.1.gz                                                                                                                                                   
/usr/share/man/man1/postkick.1.gz                                                                                                                                                  
/usr/share/man/man1/postlock.1.gz                                                                                                                                                  
/usr/share/man/man1/postlog.1.gz                                                                                                                                                   
/usr/share/man/man1/postmap.1.gz                                                                                                                                                   
/usr/share/man/man1/postmulti.1.gz                                                                                                                                                 
/usr/share/man/man1/postqueue.1.gz                                                                                                                                                 
/usr/share/man/man1/postsuper.1.gz                                                                                                                                                 
/usr/share/man/man1/sendmail.postfix.1.gz                                                                                                                                          
/usr/share/man/man1/smtp-sink.1.gz                                                                                                                                                 
/usr/share/man/man1/smtp-source.1.gz                                                                                                                                               
/usr/share/man/man5/access.5.gz                                                                                                                                                    
/usr/share/man/man5/aliases.5.gz                                                                                                                                                   
/usr/share/man/man5/aliases.postfix.5.gz                                                                                                                                           
/usr/share/man/man5/body_checks.5.gz                                                                                                                                               
/usr/share/man/man5/bounce.5.gz                                                                                                                                                    
/usr/share/man/man5/canonical.5.gz                                                                                                                                                 
/usr/share/man/man5/cidr_table.5.gz                                                                                                                                                
/usr/share/man/man5/generic.5.gz                                                                                                                                                   
/usr/share/man/man5/header_checks.5.gz                                                                                                                                             
/usr/share/man/man5/ldap_table.5.gz                                                                                                                                                
/usr/share/man/man5/lmdb_table.5.gz                                                                                                                                                
/usr/share/man/man5/master.5.gz                                                                                                                                                    
/usr/share/man/man5/memcache_table.5.gz                                                                                                                                            
/usr/share/man/man5/mysql_table.5.gz                                                                                                                                               
/usr/share/man/man5/nisplus_table.5.gz
/usr/share/man/man5/pcre_table.5.gz
/usr/share/man/man5/pgsql_table.5.gz
/usr/share/man/man5/postconf.5.gz
/usr/share/man/man5/postfix-wrapper.5.gz
/usr/share/man/man5/regexp_table.5.gz
/usr/share/man/man5/relocated.5.gz
/usr/share/man/man5/socketmap_table.5.gz
/usr/share/man/man5/sqlite_table.5.gz
/usr/share/man/man5/tcp_table.5.gz
/usr/share/man/man5/transport.5.gz
/usr/share/man/man5/virtual.5.gz
/usr/share/man/man8/anvil.8.gz
/usr/share/man/man8/bounce.8.gz
/usr/share/man/man8/cleanup.8.gz
/usr/share/man/man8/defer.8.gz
/usr/share/man/man8/discard.8.gz
/usr/share/man/man8/dnsblog.8.gz
/usr/share/man/man8/error.8.gz
/usr/share/man/man8/flush.8.gz
/usr/share/man/man8/lmtp.8.gz
/usr/share/man/man8/local.8.gz
/usr/share/man/man8/master.8.gz
/usr/share/man/man8/oqmgr.8.gz
/usr/share/man/man8/pickup.8.gz
/usr/share/man/man8/pipe.8.gz
/usr/share/man/man8/postscreen.8.gz
/usr/share/man/man8/proxymap.8.gz
/usr/share/man/man8/qmgr.8.gz
/usr/share/man/man8/qmqpd.8.gz
/usr/share/man/man8/scache.8.gz
/usr/share/man/man8/sendmail.8.gz
/usr/share/man/man8/showq.8.gz
/usr/share/man/man8/smtp.8.gz
/usr/share/man/man8/smtpd.8.gz
/usr/share/man/man8/spawn.8.gz
/usr/share/man/man8/tlsmgr.8.gz
/usr/share/man/man8/tlsproxy.8.gz
/usr/share/man/man8/trace.8.gz
/usr/share/man/man8/trivial-rewrite.8.gz
/usr/share/man/man8/verify.8.gz
/usr/share/man/man8/virtual.8.gz
/var/lib/misc/postfix.aliasesdb-stamp
/var/lib/postfix
/var/spool/postfix
/var/spool/postfix/active
/var/spool/postfix/bounce
/var/spool/postfix/corrupt
/var/spool/postfix/defer
/var/spool/postfix/deferred
/var/spool/postfix/flush
/var/spool/postfix/hold
/var/spool/postfix/incoming
/var/spool/postfix/maildrop
/var/spool/postfix/pid
/var/spool/postfix/private
/var/spool/postfix/public
/var/spool/postfix/saved
/var/spool/postfix/trace

Zuvor widmen wir aber den beiden Hauptkonfigurationsdateien main.cf und master.cf unsere Aufmerksamkeit.

Der Großteil der Konfiguration von Postfix erfolgt über /etc/postfix/main.cf. Desweiteren spielt die /etc/postfix/master.cf und weitere Dateien eine entscheidende Rolle.

All diese Dateien befinden sich im Konfigurationsverzeichnis /etc/postfix

/etc/postfix/
├── access
├── canonical
├── generic
├── header_checks
├── main.cf
├── master.cf
├── relocated
├── transport
└── virtual

Als erstes sehen wir uns die Hauptkonfigurationsdatei /etc/postfix/master.cf etwas genauer an.

Die Steuerung der in der Übersichtskizze von Postfix dargestellten Daemone und Module erfolgt mit Hilfe des master-Daemon und seiner Konfigurationsdatei master.cf, welches den Postfix-Main-Prozess definiert. Dieser Master-Prozess steuert und überwacht zum einen die einzelnen Postfix-Module, definiert wie viele Instanzen den einzelnen Modulen zugewiesen werden sollen. Zum anderen werden durch den Master-Prozess in regelmäßigen Abständen die Module zum Verwalten und Steuern der Queues gestartet.

Zur besseren Erklärung wurden die einzelnen Dienste und Befehle in der nachfolgenden Konfigurationsdatei mit Links zu den zugehörigen erklärenden Abschnitte der Wikiseite Postfix, der sichere Mailserver (MTA) unter CentOS 7.x versehen!

 # vim /etc/postfix/master.cf

/etc/postfix/master.cf
#
# Postfix master process configuration file.  For details on the format
# of the file, see the  master(5) manual page (command: "man 5 master" or
# on-line:  http://www.postfix.org/master.5.html).
#
# Do not forget to execute "postfix reload" after editing this file.
#
# ==========================================================================
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (100)
# ==========================================================================
smtp      inet  n       -       n       -       -       smtpd
#smtp      inet  n       -       n       -       1       postscreen
#smtpd     pass  -       -       n       -       -       smtpd
#dnsblog   unix  -       -       n       -       0       dnsblog
#tlsproxy  unix  -       -       n       -       0       tlsproxy
#submission inet n       -       n       -       -       smtpd
#  -o syslog_name=postfix/submission
#  -o smtpd_tls_security_level=encrypt
#  -o smtpd_sasl_auth_enable=yes
#  -o smtpd_reject_unlisted_recipient=no
#  -o smtpd_client_restrictions=$mua_client_restrictions
#  -o smtpd_helo_restrictions=$mua_helo_restrictions
#  -o smtpd_sender_restrictions=$mua_sender_restrictions
#  -o smtpd_recipient_restrictions=
#  -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
#smtps     inet  n       -       n       -       -       smtpd
#  -o syslog_name=postfix/smtps
#  -o smtpd_tls_wrappermode=yes
#  -o smtpd_sasl_auth_enable=yes
#  -o smtpd_reject_unlisted_recipient=no
#  -o smtpd_client_restrictions=$mua_client_restrictions
#  -o smtpd_helo_restrictions=$mua_helo_restrictions
#  -o smtpd_sender_restrictions=$mua_sender_restrictions
#  -o smtpd_recipient_restrictions=
#  -o smtpd_relay_restrictions=permit_sasl_authenticated,reject
#  -o milter_macro_daemon_name=ORIGINATING
#628       inet  n       -       n       -       -       qmqpd
pickup    unix  n       -       n       60      1       pickup
cleanup   unix  n       -       n       -       0       cleanup
qmgr      unix  n       -       n       300     1       qmgr
#qmgr     unix  n       -       n       300     1       oqmgr
tlsmgr    unix  -       -       n       1000?   1       tlsmgr
rewrite   unix  -       -       n       -       -       trivial-rewrite
bounce    unix  -       -       n       -       0       bounce
defer     unix  -       -       n       -       0       bounce
trace     unix  -       -       n       -       0       bounce
verify    unix  -       -       n       -       1       verify
flush     unix  n       -       n       1000?   0       flush
proxymap  unix  -       -       n       -       -       proxymap
proxwrite unix  -       -       n       -       1       proxymap
smtp      unix  -       -       n       -       -       smtp
relay     unix  -       -       n       -       -       smtp
#       -o smtp_helo_timeout=5 -o smtp_connect_timeout=5
showq     unix  n       -       n       -       -       showq
error     unix  -       -       n       -       -       error
retry     unix  -       -       n       -       -       error
discard   unix  -       -       n       -       -       discard
local     unix  -       n       n       -       -       local
virtual   unix  -       n       n       -       -       virtual
lmtp      unix  -       -       n       -       -       lmtp
anvil     unix  -       -       n       -       1       anvil
scache    unix  -       -       n       -       1       scache
#
# ====================================================================
# Interfaces to non-Postfix software. Be sure to examine the manual
# pages of the non-Postfix software to find out what options it wants.
#
# Many of the following services use the Postfix pipe(8) delivery
# agent.  See the pipe(8) man page for information about ${recipient}
# and other message envelope options.
# ====================================================================
#
# maildrop. See the Postfix MAILDROP_README file for details.
# Also specify in main.cf: maildrop_destination_recipient_limit=1
#
#maildrop  unix  -       n       n       -       -       pipe
#  flags=DRhu user=vmail argv=/usr/local/bin/maildrop -d ${recipient}
#
# ====================================================================
#
# Recent Cyrus versions can use the existing "lmtp" master.cf entry.
#
# Specify in cyrus.conf:
#   lmtp    cmd="lmtpd -a" listen="localhost:lmtp" proto=tcp4
#
# Specify in main.cf one or more of the following:
#  mailbox_transport = lmtp:inet:localhost
#  virtual_transport = lmtp:inet:localhost
#
# ====================================================================
#
# Cyrus 2.1.5 (Amos Gouaux)
# Also specify in main.cf: cyrus_destination_recipient_limit=1
#
#cyrus     unix  -       n       n       -       -       pipe
#  user=cyrus argv=/usr/lib/cyrus-imapd/deliver -e -r ${sender} -m ${extension} ${user}
#
# ====================================================================
#
# Old example of delivery via Cyrus.
#
#old-cyrus unix  -       n       n       -       -       pipe
#  flags=R user=cyrus argv=/usr/lib/cyrus-imapd/deliver -e -m ${extension} ${user}
#
# ====================================================================
#
# See the Postfix UUCP_README file for configuration details.
#
#uucp      unix  -       n       n       -       -       pipe
#  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
#
# ====================================================================
#
# Other external delivery methods.
#
#ifmail    unix  -       n       n       -       -       pipe
#  flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
#
#bsmtp     unix  -       n       n       -       -       pipe
#  flags=Fq. user=bsmtp argv=/usr/local/sbin/bsmtp -f $sender $nexthop $recipient
#
#scalemail-backend unix -       n       n       -       2       pipe
#  flags=R user=scalemail argv=/usr/lib/scalemail/bin/scalemail-store
#  ${nexthop} ${user} ${extension}
#
#mailman   unix  -       n       n       -       -       pipe
#  flags=FR user=list argv=/usr/lib/mailman/bin/postfix-to-mailman.py
#  ${nexthop} ${user}

Die eigentliche Konfiguration unseres Postfix MTAs erfolgt mit Hilfe der Hauptkonfigurationsdatei main.cf. Diese Konfigurationsdatei ist durch die vielen sehr guten Dokumentationshinweise doch sehr angewachsen, aber im Grunde beschränkt sich diese auf ein paar wenige „aktive“ Zeilen.

In der Standardkonfiguration sind alle wichtigen Parameter bereits mit einem Default-wert vorbelegt.

So hat Postfix 2.10 816 Defaultparameter.

 # postconf -d | grep mail_version
 mail_version = 2.10.1
 milter_macro_v = $mail_name $mail_version
 # postconf -d | wc -l
 816

Postfix 2.11 bringt uns 832 Defaultparameter mit.

 # postconf -d | grep mail_version
 mail_version = 2.11.6
 milter_macro_v = $mail_name $mail_version
 # postconf -d | wc -l
 847

Werfen wir einfach einen Blick in diese Hauptkonfigurationmsdatei /etc/postfix/main.cf.

 # less /etc/postfix/main.cf
/etc/postfix/main.cf
# Global Postfix configuration file. This file lists only a subset                        
# of all parameters. For the syntax, and for a complete parameter                         
# list, see the postconf(5) manual page (command: "man 5 postconf").                      
#                                                                                         
# For common configuration examples, see BASIC_CONFIGURATION_README                       
# and STANDARD_CONFIGURATION_README. To find these documents, use                         
# the command "postconf html_directory readme_directory", or go to                        
# http://www.postfix.org/BASIC_CONFIGURATION_README.html etc.                             
#                                                                                         
# For best results, change no more than 2-3 parameters at a time,                         
# and test if Postfix still works after every change.                                     
 
# SOFT BOUNCE
#            
# The soft_bounce parameter provides a limited safety net for
# testing.  When soft_bounce is enabled, mail will remain queued that
# would otherwise bounce. This parameter disables locally-generated  
# bounces, and prevents the SMTP server from rejecting mail permanently
# (by changing 5xx replies into 4xx replies). However, soft_bounce     
# is no cure for address rewriting mistakes or mail routing mistakes.  
#                                                                      
#soft_bounce = no                                                      
 
# LOCAL PATHNAME INFORMATION
#                           
# The queue_directory specifies the location of the Postfix queue.
# This is also the root directory of Postfix daemons that run chrooted.
# See the files in examples/chroot-setup for setting up Postfix chroot 
# environments on different UNIX systems.                              
#                                                                      
queue_directory = /var/spool/postfix                                   
 
# The command_directory parameter specifies the location of all
# postXXX commands.                                            
#                                                              
command_directory = /usr/sbin                                  
 
# The daemon_directory parameter specifies the location of all Postfix
# daemon programs (i.e. programs listed in the master.cf file). This  
# directory must be owned by root.                                    
#                                                                     
daemon_directory = /usr/libexec/postfix                               
 
# The data_directory parameter specifies the location of Postfix-writable
# data files (caches, random numbers). This directory must be owned      
# by the mail_owner account (see below).                                 
#                                                                        
data_directory = /var/lib/postfix                                        
 
# QUEUE AND PROCESS OWNERSHIP
#                            
# The mail_owner parameter specifies the owner of the Postfix queue
# and of most Postfix daemon processes.  Specify the name of a user
# account THAT DOES NOT SHARE ITS USER OR GROUP ID WITH OTHER ACCOUNTS
# AND THAT OWNS NO OTHER FILES OR PROCESSES ON THE SYSTEM.  In        
# particular, don't specify nobody or daemon. PLEASE USE A DEDICATED  
# USER.                                                               
#                                                                     
mail_owner = postfix                                                  
 
# The default_privs parameter specifies the default rights used by
# the local delivery agent for delivery to external file or command.
# These rights are used in the absence of a recipient user context. 
# DO NOT SPECIFY A PRIVILEGED USER OR THE POSTFIX OWNER.            
#                                                                   
#default_privs = nobody                                             
 
# INTERNET HOST AND DOMAIN NAMES
#                               
# The myhostname parameter specifies the internet hostname of this
# mail system. The default is to use the fully-qualified domain name
# from gethostname(). $myhostname is used as a default value for many
# other configuration parameters.                                    
#                                                                    
#myhostname = host.domain.tld                                        
#myhostname = virtual.domain.tld                                     
 
# The mydomain parameter specifies the local internet domain name.
# The default is to use $myhostname minus the first component.    
# $mydomain is used as a default value for many other configuration
# parameters.                                                      
#                                                                  
#mydomain = domain.tld                                             
 
# SENDING MAIL
#             
# The myorigin parameter specifies the domain that locally-posted
# mail appears to come from. The default is to append $myhostname,
# which is fine for small sites.  If you run a domain with multiple
# machines, you should (1) change this to $mydomain and (2) set up 
# a domain-wide alias database that aliases each user to           
# user@that.users.mailhost.                                        
#                                                                  
# For the sake of consistency between sender and recipient addresses,
# myorigin also specifies the default domain name that is appended   
# to recipient addresses that have no @domain part.                  
#                                                                    
#myorigin = $myhostname                                              
#myorigin = $mydomain                                                
 
# RECEIVING MAIL
 
# The inet_interfaces parameter specifies the network interface
# addresses that this mail system receives mail on.  By default,
# the software claims all active interfaces on the machine. The 
# parameter also controls delivery of mail to user@[ip.address].
#                                                               
# See also the proxy_interfaces parameter, for network addresses that
# are forwarded to us via a proxy or network address translator.     
#                                                                    
# Note: you need to stop/start Postfix when this parameter changes.  
#                                                                    
#inet_interfaces = all                                               
#inet_interfaces = $myhostname                                       
#inet_interfaces = $myhostname, localhost                            
inet_interfaces = localhost                                          
 
# Enable IPv4, and IPv6 if supported
inet_protocols = all                
 
# The proxy_interfaces parameter specifies the network interface
# addresses that this mail system receives mail on by way of a  
# proxy or network address translation unit. This setting extends
# the address list specified with the inet_interfaces parameter. 
#                                                                
# You must specify your proxy/NAT addresses when your system is a
# backup MX host for other domains, otherwise mail delivery loops
# will happen when the primary MX host is down.                  
#                                                                
#proxy_interfaces =                                              
#proxy_interfaces = 1.2.3.4                                      
 
# The mydestination parameter specifies the list of domains that this
# machine considers itself the final destination for.                
#                                                                    
# These domains are routed to the delivery agent specified with the  
# local_transport parameter setting. By default, that is the UNIX    
# compatible delivery agent that lookups all recipients in /etc/passwd
# and /etc/aliases or their equivalent.                               
#                                                                     
# The default is $myhostname + localhost.$mydomain.  On a mail domain 
# gateway, you should also include $mydomain.                         
#                                                                     
# Do not specify the names of virtual domains - those domains are     
# specified elsewhere (see VIRTUAL_README).                           
#                                                                     
# Do not specify the names of domains that this machine is backup MX  
# host for. Specify those names via the relay_domains settings for    
# the SMTP server, or use permit_mx_backup if you are lazy (see       
# STANDARD_CONFIGURATION_README).                                     
#                                                                     
# The local machine is always the final destination for mail addressed
# to user@[the.net.work.address] of an interface that the mail system 
# receives mail on (see the inet_interfaces parameter).               
#                                                                     
# Specify a list of host or domain names, /file/name or type:table    
# patterns, separated by commas and/or whitespace. A /file/name       
# pattern is replaced by its contents; a type:table is matched when   
# a name matches a lookup key (the right-hand side is ignored).       
# Continue long lines by starting the next line with whitespace.      
#                                                                     
# See also below, section "REJECTING MAIL FOR UNKNOWN LOCAL USERS".   
#                                                                     
mydestination = $myhostname, localhost.$mydomain, localhost           
#mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
#mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain,
#       mail.$mydomain, www.$mydomain, ftp.$mydomain                    
 
# REJECTING MAIL FOR UNKNOWN LOCAL USERS
#                                       
# The local_recipient_maps parameter specifies optional lookup tables
# with all names or addresses of users that are local with respect   
# to $mydestination, $inet_interfaces or $proxy_interfaces.          
#                                                                    
# If this parameter is defined, then the SMTP server will reject     
# mail for unknown local users. This parameter is defined by default.
#                                                                    
# To turn off local recipient checking in the SMTP server, specify   
# local_recipient_maps = (i.e. empty).                               
#                                                                    
# The default setting assumes that you use the default Postfix local 
# delivery agent for local delivery. You need to update the          
# local_recipient_maps setting if:                                   
#                                                                    
# - You define $mydestination domain recipients in files other than  
#   /etc/passwd, /etc/aliases, or the $virtual_alias_maps files.     
#   For example, you define $mydestination domain recipients in      
#   the $virtual_mailbox_maps files.                                 
#                                                                    
# - You redefine the local delivery agent in master.cf.              
#                                                                    
# - You redefine the "local_transport" setting in main.cf.           
#                                                                    
# - You use the "luser_relay", "mailbox_transport", or "fallback_transport"
#   feature of the Postfix local delivery agent (see local(8)).            
#                                                                          
# Details are described in the LOCAL_RECIPIENT_README file.                
#                                                                          
# Beware: if the Postfix SMTP server runs chrooted, you probably have      
# to access the passwd file via the proxymap service, in order to          
# overcome chroot restrictions. The alternative, having a copy of          
# the system passwd file in the chroot jail is just not practical.         
#                                                                          
# The right-hand side of the lookup tables is conveniently ignored.        
# In the left-hand side, specify a bare username, an @domain.tld           
# wild-card, or specify a user@domain.tld address.                         
#                                                                          
#local_recipient_maps = unix:passwd.byname $alias_maps                     
#local_recipient_maps = proxy:unix:passwd.byname $alias_maps               
#local_recipient_maps =                                                    
 
# The unknown_local_recipient_reject_code specifies the SMTP server
# response code when a recipient domain matches $mydestination or  
# ${proxy,inet}_interfaces, while $local_recipient_maps is non-empty
# and the recipient address or address local-part is not found.     
#                                                                   
# The default setting is 550 (reject mail) but it is safer to start 
# with 450 (try again later) until you are certain that your        
# local_recipient_maps settings are OK.                             
#                                                                   
unknown_local_recipient_reject_code = 550                           
 
# TRUST AND RELAY CONTROL
 
# The mynetworks parameter specifies the list of "trusted" SMTP
# clients that have more privileges than "strangers".          
#                                                              
# In particular, "trusted" SMTP clients are allowed to relay mail
# through Postfix.  See the smtpd_recipient_restrictions parameter
# in postconf(5).                                                 
#                                                                 
# You can specify the list of "trusted" network addresses by hand 
# or you can let Postfix do it for you (which is the default).    
#                                                                 
# By default (mynetworks_style = subnet), Postfix "trusts" SMTP   
# clients in the same IP subnetworks as the local machine.        
# On Linux, this does works correctly only with interfaces specified
# with the "ifconfig" command.                                      
#                                                                   
# Specify "mynetworks_style = class" when Postfix should "trust" SMTP
# clients in the same IP class A/B/C networks as the local machine.  
# Don't do this with a dialup site - it would cause Postfix to "trust"
# your entire provider's network.  Instead, specify an explicit       
# mynetworks list by hand, as described below.                        
#                                                                     
# Specify "mynetworks_style = host" when Postfix should "trust"       
# only the local machine.                                             
#                                                                     
#mynetworks_style = class                                             
#mynetworks_style = subnet                                            
#mynetworks_style = host                                              
 
# Alternatively, you can specify the mynetworks list by hand, in
# which case Postfix ignores the mynetworks_style setting.      
#                                                               
# Specify an explicit list of network/netmask patterns, where the
# mask specifies the number of bits in the network part of a host
# address.                                                       
#                                                                
# You can also specify the absolute pathname of a pattern file instead
# of listing the patterns here. Specify type:table for table-based lookups
# (the value on the table right-hand side is not used).                   
#                                                                         
#mynetworks = 168.100.189.0/28, 127.0.0.0/8                               
#mynetworks = $config_directory/mynetworks                                
#mynetworks = hash:/etc/postfix/network_table                             
 
# The relay_domains parameter restricts what destinations this system will
# relay mail to.  See the smtpd_recipient_restrictions description in     
# postconf(5) for detailed information.                                   
#                                                                         
# By default, Postfix relays mail                                         
# - from "trusted" clients (IP address matches $mynetworks) to any destination,
# - from "untrusted" clients to destinations that match $relay_domains or      
#   subdomains thereof, except addresses with sender-specified routing.        
# The default relay_domains value is $mydestination.                           
#                                                                              
# In addition to the above, the Postfix SMTP server by default accepts mail    
# that Postfix is final destination for:                                       
# - destinations that match $inet_interfaces or $proxy_interfaces,             
# - destinations that match $mydestination                                     
# - destinations that match $virtual_alias_domains,                            
# - destinations that match $virtual_mailbox_domains.                          
# These destinations do not need to be listed in $relay_domains.               
#                                                                              
# Specify a list of hosts or domains, /file/name patterns or type:name         
# lookup tables, separated by commas and/or whitespace.  Continue              
# long lines by starting the next line with whitespace. A file name            
# is replaced by its contents; a type:name table is matched when a             
# (parent) domain appears as lookup key.                                       
#                                                                              
# NOTE: Postfix will not automatically forward mail for domains that           
# list this system as their primary or backup MX host. See the                 
# permit_mx_backup restriction description in postconf(5).                     
#                                                                              
#relay_domains = $mydestination                                                
 
# INTERNET OR INTRANET
 
# The relayhost parameter specifies the default host to send mail to
# when no entry is matched in the optional transport(5) table. When 
# no relayhost is given, mail is routed directly to the destination.
#                                                                   
# On an intranet, specify the organizational domain name. If your   
# internal DNS uses no MX records, specify the name of the intranet 
# gateway host instead.                                             
#                                                                   
# In the case of SMTP, specify a domain, host, host:port, [host]:port,
# [address] or [address]:port; the form [host] turns off MX lookups.  
#                                                                     
# If you're connected via UUCP, see also the default_transport parameter.
#                                                                        
#relayhost = $mydomain                                                   
#relayhost = [gateway.my.domain]                                         
#relayhost = [mailserver.isp.tld]                                        
#relayhost = uucphost                                                    
#relayhost = [an.ip.add.ress]                                            
 
# REJECTING UNKNOWN RELAY USERS
#                              
# The relay_recipient_maps parameter specifies optional lookup tables
# with all addresses in the domains that match $relay_domains.       
#                                                                    
# If this parameter is defined, then the SMTP server will reject     
# mail for unknown relay users. This feature is off by default.      
#                                                                    
# The right-hand side of the lookup tables is conveniently ignored.  
# In the left-hand side, specify an @domain.tld wild-card, or specify
# a user@domain.tld address.                                         
#                                                                    
#relay_recipient_maps = hash:/etc/postfix/relay_recipients           
 
# INPUT RATE CONTROL
#                   
# The in_flow_delay configuration parameter implements mail input
# flow control. This feature is turned on by default, although it
# still needs further development (it's disabled on SCO UNIX due 
# to an SCO bug).                                                
#                                                                
# A Postfix process will pause for $in_flow_delay seconds before 
# accepting a new message, when the message arrival rate exceeds the
# message delivery rate. With the default 100 SMTP server process   
# limit, this limits the mail inflow to 100 messages a second more  
# than the number of messages delivered per second.                 
#                                                                   
# Specify 0 to disable the feature. Valid delays are 0..10.         
#                                                                   
#in_flow_delay = 1s                                                 
 
# ADDRESS REWRITING
#                  
# The ADDRESS_REWRITING_README document gives information about
# address masquerading or other forms of address rewriting including
# username->Firstname.Lastname mapping.                             
 
# ADDRESS REDIRECTION (VIRTUAL DOMAIN)
#                                     
# The VIRTUAL_README document gives information about the many forms
# of domain hosting that Postfix supports.                          
 
# "USER HAS MOVED" BOUNCE MESSAGES
#                                 
# See the discussion in the ADDRESS_REWRITING_README document.
 
# TRANSPORT MAP
#              
# See the discussion in the ADDRESS_REWRITING_README document.
 
# ALIAS DATABASE
#               
# The alias_maps parameter specifies the list of alias databases used
# by the local delivery agent. The default list is system dependent. 
#                                                                    
# On systems with NIS, the default is to search the local alias      
# database, then the NIS alias database. See aliases(5) for syntax   
# details.                                                           
#                                                                    
# If you change the alias database, run "postalias /etc/aliases" (or 
# wherever your system stores the mail alias file), or simply run    
# "newaliases" to build the necessary DBM or DB file.                
#                                                                    
# It will take a minute or so before changes become visible.  Use    
# "postfix reload" to eliminate the delay.                           
#                                                                    
#alias_maps = dbm:/etc/aliases                                       
alias_maps = hash:/etc/aliases                                       
#alias_maps = hash:/etc/aliases, nis:mail.aliases                    
#alias_maps = netinfo:/aliases                                       
 
# The alias_database parameter specifies the alias database(s) that
# are built with "newaliases" or "sendmail -bi".  This is a separate
# configuration parameter, because alias_maps (see above) may specify
# tables that are not necessarily all under control by Postfix.      
#                                                                    
#alias_database = dbm:/etc/aliases                                   
#alias_database = dbm:/etc/mail/aliases                              
alias_database = hash:/etc/aliases                                   
#alias_database = hash:/etc/aliases, hash:/opt/majordomo/aliases     
 
# ADDRESS EXTENSIONS (e.g., user+foo)
#                                    
# The recipient_delimiter parameter specifies the separator between
# user names and address extensions (user+foo). See canonical(5),  
# local(8), relocated(5) and virtual(5) for the effects this has on
# aliases, canonical, virtual, relocated and .forward file lookups.
# Basically, the software tries user+foo and .forward+foo before   
# trying user and .forward.                                        
#                                                                  
#recipient_delimiter = +                                           
 
# DELIVERY TO MAILBOX
#                    
# The home_mailbox parameter specifies the optional pathname of a
# mailbox file relative to a user's home directory. The default  
# mailbox file is /var/spool/mail/user or /var/mail/user.  Specify
# "Maildir/" for qmail-style delivery (the / is required).        
#                                                                 
#home_mailbox = Mailbox                                           
#home_mailbox = Maildir/                                          
 
# The mail_spool_directory parameter specifies the directory where
# UNIX-style mailboxes are kept. The default setting depends on the
# system type.                                                     
#                                                                  
#mail_spool_directory = /var/mail                                  
#mail_spool_directory = /var/spool/mail                            
 
# The mailbox_command parameter specifies the optional external
# command to use instead of mailbox delivery. The command is run as
# the recipient with proper HOME, SHELL and LOGNAME environment settings.
# Exception:  delivery for root is done as $default_user.                
#                                                                        
# Other environment variables of interest: USER (recipient username),    
# EXTENSION (address extension), DOMAIN (domain part of address),        
# and LOCAL (the address localpart).                                     
#                                                                        
# Unlike other Postfix configuration parameters, the mailbox_command     
# parameter is not subjected to $parameter substitutions. This is to     
# make it easier to specify shell syntax (see example below).            
#                                                                        
# Avoid shell meta characters because they will force Postfix to run     
# an expensive shell process. Procmail alone is expensive enough.        
#                                                                        
# IF YOU USE THIS TO DELIVER MAIL SYSTEM-WIDE, YOU MUST SET UP AN        
# ALIAS THAT FORWARDS MAIL FOR ROOT TO A REAL USER.                      
#                                                                        
#mailbox_command = /some/where/procmail                                  
#mailbox_command = /some/where/procmail -a "$EXTENSION"                  
 
# The mailbox_transport specifies the optional transport in master.cf
# to use after processing aliases and .forward files. This parameter 
# has precedence over the mailbox_command, fallback_transport and    
# luser_relay parameters.                                            
#                                                                    
# Specify a string of the form transport:nexthop, where transport is 
# the name of a mail delivery transport defined in master.cf.  The   
# :nexthop part is optional. For more details see the sample transport
# configuration file.                                                 
#                                                                     
# NOTE: if you use this feature for accounts not in the UNIX password 
# file, then you must update the "local_recipient_maps" setting in    
# the main.cf file, otherwise the SMTP server will reject mail for    
# non-UNIX accounts with "User unknown in local recipient table".     
#                                                                     
# Cyrus IMAP over LMTP. Specify ``lmtpunix      cmd="lmtpd"           
# listen="/var/imap/socket/lmtp" prefork=0'' in cyrus.conf.           
#mailbox_transport = lmtp:unix:/var/lib/imap/socket/lmtp              
 
# If using the cyrus-imapd IMAP server deliver local mail to the IMAP
# server using LMTP (Local Mail Transport Protocol), this is prefered
# over the older cyrus deliver program by setting the                
# mailbox_transport as below:                                        
#                                                                    
# mailbox_transport = lmtp:unix:/var/lib/imap/socket/lmtp            
#                                                                    
# The efficiency of LMTP delivery for cyrus-imapd can be enhanced via
# these settings.                                                    
#                                                                    
# local_destination_recipient_limit = 300                            
# local_destination_concurrency_limit = 5                            
#                                                                    
# Of course you should adjust these settings as appropriate for the  
# capacity of the hardware you are using. The recipient limit setting
# can be used to take advantage of the single instance message store 
# capability of Cyrus. The concurrency limit can be used to control  
# how many simultaneous LMTP sessions will be permitted to the Cyrus 
# message store.                                                     
#                                                                    
# Cyrus IMAP via command line. Uncomment the "cyrus...pipe" and      
# subsequent line in master.cf.                                      
#mailbox_transport = cyrus                                           
 
# The fallback_transport specifies the optional transport in master.cf
# to use for recipients that are not found in the UNIX passwd database.
# This parameter has precedence over the luser_relay parameter.        
#                                                                      
# Specify a string of the form transport:nexthop, where transport is   
# the name of a mail delivery transport defined in master.cf.  The     
# :nexthop part is optional. For more details see the sample transport 
# configuration file.                                                  
#                                                                      
# NOTE: if you use this feature for accounts not in the UNIX password  
# file, then you must update the "local_recipient_maps" setting in     
# the main.cf file, otherwise the SMTP server will reject mail for     
# non-UNIX accounts with "User unknown in local recipient table".      
#                                                                      
#fallback_transport = lmtp:unix:/var/lib/imap/socket/lmtp              
#fallback_transport =                                                  
 
# The luser_relay parameter specifies an optional destination address
# for unknown recipients.  By default, mail for unknown@$mydestination,
# unknown@[$inet_interfaces] or unknown@[$proxy_interfaces] is returned
# as undeliverable.                                                    
#                                                                      
# The following expansions are done on luser_relay: $user (recipient   
# username), $shell (recipient shell), $home (recipient home directory),
# $recipient (full recipient address), $extension (recipient address    
# extension), $domain (recipient domain), $local (entire recipient      
# localpart), $recipient_delimiter. Specify ${name?value} or            
# ${name:value} to expand value only when $name does (does not) exist.  
#                                                                       
# luser_relay works only for the default Postfix local delivery agent.  
#                                                                       
# NOTE: if you use this feature for accounts not in the UNIX password   
# file, then you must specify "local_recipient_maps =" (i.e. empty) in  
# the main.cf file, otherwise the SMTP server will reject mail for      
# non-UNIX accounts with "User unknown in local recipient table".       
#                                                                       
#luser_relay = $user@other.host                                         
#luser_relay = $local@other.host                                        
#luser_relay = admin+$local                                             
 
# JUNK MAIL CONTROLS                                                    
#                                                                       
# The controls listed here are only a very small subset. The file       
# SMTPD_ACCESS_README provides an overview.                             
 
# The header_checks parameter specifies an optional table with patterns
# that each logical message header is matched against, including       
# headers that span multiple physical lines.                           
#                                                                      
# By default, these patterns also apply to MIME headers and to the     
# headers of attached messages. With older Postfix versions, MIME and  
# attached message headers were treated as body text.                  
#                                                                      
# For details, see "man header_checks".                                
#                                                                      
#header_checks = regexp:/etc/postfix/header_checks                     
 
# FAST ETRN SERVICE
#                  
# Postfix maintains per-destination logfiles with information about
# deferred mail, so that mail can be flushed quickly with the SMTP 
# "ETRN domain.tld" command, or by executing "sendmail -qRdomain.tld".
# See the ETRN_README document for a detailed description.            
#                                                                     
# The fast_flush_domains parameter controls what destinations are     
# eligible for this service. By default, they are all domains that    
# this server is willing to relay mail to.                            
#                                                                     
#fast_flush_domains = $relay_domains                                  
 
# SHOW SOFTWARE VERSION OR NOT
#                             
# The smtpd_banner parameter specifies the text that follows the 220
# code in the SMTP server's greeting banner. Some people like to see
# the mail version advertised. By default, Postfix shows no version.
#                                                                   
# You MUST specify $myhostname at the start of the text. That is an 
# RFC requirement. Postfix itself does not care.                    
#                                                                   
#smtpd_banner = $myhostname ESMTP $mail_name                        
#smtpd_banner = $myhostname ESMTP $mail_name ($mail_version)        
 
# PARALLEL DELIVERY TO THE SAME DESTINATION
#                                          
# How many parallel deliveries to the same user or domain? With local
# delivery, it does not make sense to do massively parallel delivery 
# to the same user, because mailbox updates must happen sequentially,
# and expensive pipelines in .forward files can cause disasters when 
# too many are run at the same time. With SMTP deliveries, 10        
# simultaneous connections to the same domain could be sufficient to 
# raise eyebrows.                                                    
#                                                                    
# Each message delivery transport has its XXX_destination_concurrency_limit
# parameter.  The default is $default_destination_concurrency_limit for    
# most delivery transports. For the local delivery agent the default is 2. 
 
#local_destination_concurrency_limit = 2
#default_destination_concurrency_limit = 20
 
# DEBUGGING CONTROL
#                  
# The debug_peer_level parameter specifies the increment in verbose
# logging level when an SMTP client or server host name or address 
# matches a pattern in the debug_peer_list parameter.              
#                                                                  
debug_peer_level = 2                                               
 
# The debug_peer_list parameter specifies an optional list of domain
# or network patterns, /file/name patterns or type:name tables. When
# an SMTP client or server host name or address matches a pattern,  
# increase the verbose logging level by the amount specified in the 
# debug_peer_level parameter.                                       
#                                                                   
#debug_peer_list = 127.0.0.1                                        
#debug_peer_list = some.domain                                      
 
# The debugger_command specifies the external command that is executed
# when a Postfix daemon program is run with the -D option.            
#                                                                     
# Use "command .. & sleep 5" so that the debugger can attach before   
# the process marches on. If you use an X-based debugger, be sure to  
# set up your XAUTHORITY environment variable before starting Postfix.
#                                                                     
debugger_command =                                                    
         PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin             
         ddd $daemon_directory/$process_name $process_id & sleep 5    
 
# If you can't use X, use this to capture the call stack when a
# daemon crashes. The result is in a file in the configuration 
# directory, and is named after the process name and the process ID.
#                                                                   
# debugger_command =                                                
#       PATH=/bin:/usr/bin:/usr/local/bin; export PATH; (echo cont; 
#       echo where) | gdb $daemon_directory/$process_name $process_id 2>&1
#       >$config_directory/$process_name.$process_id.log & sleep 5
#
# Another possibility is to run gdb under a detached screen session.
# To attach to the screen sesssion, su root and run "screen -r
# <id_string>" where <id_string> uniquely matches one of the detached
# sessions (from "screen -list").
#
# debugger_command =
#       PATH=/bin:/usr/bin:/sbin:/usr/sbin; export PATH; screen
#       -dmS $process_name gdb $daemon_directory/$process_name
#       $process_id & sleep 1
 
# INSTALL-TIME CONFIGURATION INFORMATION
#
# The following parameters are used when installing a new Postfix version.
#
# sendmail_path: The full pathname of the Postfix sendmail command.
# This is the Sendmail-compatible mail posting interface.
#
sendmail_path = /usr/sbin/sendmail.postfix
 
# newaliases_path: The full pathname of the Postfix newaliases command.
# This is the Sendmail-compatible command to build alias databases.
#
newaliases_path = /usr/bin/newaliases.postfix
 
# mailq_path: The full pathname of the Postfix mailq command.  This
# is the Sendmail-compatible mail queue listing command.
#
mailq_path = /usr/bin/mailq.postfix
 
# setgid_group: The group for mail submission and queue management
# commands.  This must be a group name with a numerical group ID that
# is not shared with other accounts, not even with the Postfix account.
#
setgid_group = postdrop
 
# html_directory: The location of the Postfix HTML documentation.
#
html_directory = no
 
# manpage_directory: The location of the Postfix on-line manual pages.
#
manpage_directory = /usr/share/man
 
# sample_directory: The location of the Postfix sample configuration files.
# This parameter is obsolete as of Postfix 2.1.
#
sample_directory = /usr/share/doc/postfix-2.11.1/samples
 
# readme_directory: The location of the Postfix README files.
#
readme_directory = /usr/share/doc/postfix-2.11.1/README_FILES

Mit Hilfe des Programms postconf können wir während des laufenden Betriebes einzelnen Parameter, abfragen und auch ändern. Wollen wir uns alle Definitionen ansehen, die von den Standardvorgaben abweichen, verwenden wir den folgenden Aufruf:

# postconf -n
alias_database = hash:/etc/aliases
alias_maps = hash:/etc/aliases
command_directory = /usr/sbin
config_directory = /etc/postfix
daemon_directory = /usr/libexec/postfix
data_directory = /var/lib/postfix
debug_peer_level = 2
debugger_command = PATH=/bin:/usr/bin:/usr/local/bin:/usr/X11R6/bin ddd $daemon_directory/$process_name $process_id & sleep 5
html_directory = no
inet_interfaces = localhost
inet_protocols = all
mail_owner = postfix
mailq_path = /usr/bin/mailq.postfix
manpage_directory = /usr/share/man
mydestination = $myhostname, localhost.$mydomain, localhost
newaliases_path = /usr/bin/newaliases.postfix
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.11.1/README_FILES
sample_directory = /usr/share/doc/postfix-2.11.1/samples
sendmail_path = /usr/sbin/sendmail.postfix
setgid_group = postdrop
unknown_local_recipient_reject_code = 550

Wollen wir uns alle Standard-Definitionen ansehen verwenden wir den folgenden Aufruf:

# postconf -d
2bounce_notice_recipient = postmaster                                                                                                                                              
access_map_defer_code = 450                                                                                                                                                        
access_map_reject_code = 554                                                                                                                                                       
address_verify_cache_cleanup_interval = 12h                                                                                                                                        
address_verify_default_transport = $default_transport                                                                                                                              
address_verify_local_transport = $local_transport                                                                                                                                  
address_verify_map = btree:$data_directory/verify_cache                                                                                                                            
address_verify_negative_cache = yes                                                                                                                                                
address_verify_negative_expire_time = 3d                                                                                                                                           
address_verify_negative_refresh_time = 3h                                                                                                                                          
address_verify_poll_count = ${stress?1}${stress:3}                                                                                                                                 
address_verify_poll_delay = 3s                                                                                                                                                     
address_verify_positive_expire_time = 31d                                                                                                                                          
address_verify_positive_refresh_time = 7d                                                                                                                                          
address_verify_relay_transport = $relay_transport                                                                                                                                  
address_verify_relayhost = $relayhost                                                                                                                                              
address_verify_sender = $double_bounce_sender                                                                                                                                      
address_verify_sender_dependent_default_transport_maps = $sender_dependent_default_transport_maps                                                                                  
address_verify_sender_dependent_relayhost_maps = $sender_dependent_relayhost_maps                                                                                                  
address_verify_sender_ttl = 0s                                                                                                                                                     
address_verify_service_name = verify                                                                                                                                               
address_verify_transport_maps = $transport_maps                                                                                                                                    
address_verify_virtual_transport = $virtual_transport                                                                                                                              
alias_database = hash:/etc/aliases                                                                                                                                                 
alias_maps = hash:/etc/aliases, nis:mail.aliases                                                                                                                                   
allow_mail_to_commands = alias, forward                                                                                                                                            
allow_mail_to_files = alias, forward                                                                                                                                               
allow_min_user = no                                                                                                                                                                
allow_percent_hack = yes                                                                                                                                                           
allow_untrusted_routing = no                                                                                                                                                       
alternate_config_directories =                                                                                                                                                     
always_add_missing_headers = no                                                                                                                                                    
always_bcc =                                                                                                                                                                       
anvil_rate_time_unit = 60s                                                                                                                                                         
anvil_status_update_time = 600s                                                                                                                                                    
append_at_myorigin = yes                                                                                                                                                           
append_dot_mydomain = yes                                                                                                                                                          
application_event_drain_time = 100s                                                                                                                                                
authorized_flush_users = static:anyone                                                                                                                                             
authorized_mailq_users = static:anyone                                                                                                                                             
authorized_submit_users = static:anyone                                                                                                                                            
backwards_bounce_logfile_compatibility = yes                                                                                                                                       
berkeley_db_create_buffer_size = 16777216                                                                                                                                          
berkeley_db_read_buffer_size = 131072                                                                                                                                              
best_mx_transport =                                                                                                                                                                
biff = yes                                                                                                                                                                         
body_checks =                                                                                                                                                                      
body_checks_size_limit = 51200                                                                                                                                                     
bounce_notice_recipient = postmaster                                                                                                                                               
bounce_queue_lifetime = 5d                                                                                                                                                         
bounce_service_name = bounce                                                                                                                                                       
bounce_size_limit = 50000                                                                                                                                                          
bounce_template_file =                                                                                                                                                             
broken_sasl_auth_clients = no                                                                                                                                                      
canonical_classes = envelope_sender, envelope_recipient, header_sender, header_recipient                                                                                           
canonical_maps =                                                                                                                                                                   
cleanup_service_name = cleanup                                                                                                                                                     
command_directory = /usr/sbin                                                                                                                                                      
command_execution_directory =                                                                                                                                                      
command_expansion_filter = 1234567890!@%-_=+:,./abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ                                                                               
command_time_limit = 1000s                                                                                                                                                         
config_directory = /etc/postfix                                                                                                                                                    
connection_cache_protocol_timeout = 5s                                                                                                                                             
connection_cache_service_name = scache                                                                                                                                             
connection_cache_status_update_time = 600s                                                                                                                                         
connection_cache_ttl_limit = 2s                                                                                                                                                    
content_filter =                                                                                                                                                                   
cyrus_sasl_config_path =                                                                                                                                                           
daemon_directory = /usr/libexec/postfix                                                                                                                                            
daemon_table_open_error_is_fatal = no                                                                                                                                              
daemon_timeout = 18000s                                                                                                                                                            
data_directory = /var/lib/postfix                                                                                                                                                  
debug_peer_level = 2                                                                                                                                                               
debug_peer_list =                                                                                                                                                                  
debugger_command =                                                                                                                                                                 
default_database_type = hash                                                                                                                                                       
default_delivery_slot_cost = 5                                                                                                                                                     
default_delivery_slot_discount = 50                                                                                                                                                
default_delivery_slot_loan = 3                                                                                                                                                     
default_destination_concurrency_failed_cohort_limit = 1                                                                                                                            
default_destination_concurrency_limit = 20                                                                                                                                         
default_destination_concurrency_negative_feedback = 1                                                                                                                              
default_destination_concurrency_positive_feedback = 1                                                                                                                              
default_destination_rate_delay = 0s                                                                                                                                                
default_destination_recipient_limit = 50                                                                                                                                           
default_extra_recipient_limit = 1000                                                                                                                                               
default_filter_nexthop =                                                                                                                                                           
default_minimum_delivery_slots = 3                                                                                                                                                 
default_privs = nobody                                                                                                                                                             
default_process_limit = 100                                                                                                                                                        
default_rbl_reply = $rbl_code Service unavailable; $rbl_class [$rbl_what] blocked using $rbl_domain${rbl_reason?; $rbl_reason}                                                     
default_recipient_limit = 20000                                                                                                                                                    
default_recipient_refill_delay = 5s                                                                                                                                                
default_recipient_refill_limit = 100                                                                                                                                               
default_transport = smtp                                                                                                                                                           
default_verp_delimiters = +=                                                                                                                                                       
defer_code = 450                                                                                                                                                                   
defer_service_name = defer                                                                                                                                                         
defer_transports =                                                                                                                                                                 
delay_logging_resolution_limit = 2                                                                                                                                                 
delay_notice_recipient = postmaster                                                                                                                                                
delay_warning_time = 0h                                                                                                                                                            
deliver_lock_attempts = 20                                                                                                                                                         
deliver_lock_delay = 1s                                                                                                                                                            
destination_concurrency_feedback_debug = no                                                                                                                                        
detect_8bit_encoding_header = yes                                                                                                                                                  
disable_dns_lookups = no                                                                                                                                                           
disable_mime_input_processing = no                                                                                                                                                 
disable_mime_output_conversion = no                                                                                                                                                
disable_verp_bounces = no                                                                                                                                                          
disable_vrfy_command = no                                                                                                                                                          
dnsblog_reply_delay = 0s                                                                                                                                                           
dnsblog_service_name = dnsblog                                                                                                                                                     
dont_remove = 0                                                                                                                                                                    
double_bounce_sender = double-bounce                                                                                                                                               
duplicate_filter_limit = 1000                                                                                                                                                      
empty_address_default_transport_maps_lookup_key = <>                                                                                                                               
empty_address_recipient = MAILER-DAEMON                                                                                                                                            
empty_address_relayhost_maps_lookup_key = <>                                                                                                                                       
enable_long_queue_ids = no                                                                                                                                                         
enable_original_recipient = yes                                                                                                                                                    
error_delivery_slot_cost = $default_delivery_slot_cost                                                                                                                             
error_delivery_slot_discount = $default_delivery_slot_discount                                                                                                                     
error_delivery_slot_loan = $default_delivery_slot_loan                                                                                                                             
error_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit                                                                           
error_destination_concurrency_limit = $default_destination_concurrency_limit                                                                                                       
error_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback                                                                               
error_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback                                                                               
error_destination_rate_delay = $default_destination_rate_delay                                                                                                                     
error_destination_recipient_limit = $default_destination_recipient_limit                                                                                                           
error_extra_recipient_limit = $default_extra_recipient_limit                                                                                                                       
error_initial_destination_concurrency = $initial_destination_concurrency                                                                                                           
error_minimum_delivery_slots = $default_minimum_delivery_slots                                                                                                                     
error_notice_recipient = postmaster                                                                                                                                                
error_recipient_limit = $default_recipient_limit                                                                                                                                   
error_recipient_refill_delay = $default_recipient_refill_delay                                                                                                                     
error_recipient_refill_limit = $default_recipient_refill_limit                                                                                                                     
error_service_name = error                                                                                                                                                         
execution_directory_expansion_filter = 1234567890!@%-_=+:,./abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ                                                                   
expand_owner_alias = no                                                                                                                                                            
export_environment = TZ MAIL_CONFIG LANG                                                                                                                                           
fallback_transport =                                                                                                                                                               
fallback_transport_maps =                                                                                                                                                          
fast_flush_domains = $relay_domains                                                                                                                                                
fast_flush_purge_time = 7d                                                                                                                                                         
fast_flush_refresh_time = 12h                                                                                                                                                      
fault_injection_code = 0                                                                                                                                                           
flush_service_name = flush                                                                                                                                                         
fork_attempts = 5                                                                                                                                                                  
fork_delay = 1s                                                                                                                                                                    
forward_expansion_filter = 1234567890!@%-_=+:,./abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ                                                                               
forward_path = $home/.forward${recipient_delimiter}${extension}, $home/.forward                                                                                                    
frozen_delivered_to = yes                                                                                                                                                          
hash_queue_depth = 1                                                                                                                                                               
hash_queue_names = deferred, defer                                                                                                                                                 
header_address_token_limit = 10240                                                                                                                                                 
header_checks =                                                                                                                                                                    
header_size_limit = 102400                                                                                                                                                         
helpful_warnings = yes                                                                                                                                                             
home_mailbox =                                                                                                                                                                     
hopcount_limit = 50                                                                                                                                                                
html_directory = no                                                                                                                                                                
ignore_mx_lookup_error = no                                                                                                                                                        
import_environment = MAIL_CONFIG MAIL_DEBUG MAIL_LOGTAG TZ XAUTHORITY DISPLAY LANG=C                                                                                               
in_flow_delay = 1s                                                                                                                                                                 
inet_interfaces = all                                                                                                                                                              
inet_protocols = all                                                                                                                                                               
initial_destination_concurrency = 5                                                                                                                                                
internal_mail_filter_classes =                                                                                                                                                     
invalid_hostname_reject_code = 501                                                                                                                                                 
ipc_idle = 5s                                                                                                                                                                      
ipc_timeout = 3600s                                                                                                                                                                
ipc_ttl = 1000s                                                                                                                                                                    
line_length_limit = 2048                                                                                                                                                           
lmdb_map_size = 16777216                                                                                                                                                           
lmtp_address_preference = any                                                                                                                                                      
lmtp_assume_final = no                                                                                                                                                             
lmtp_bind_address =                                                                                                                                                                
lmtp_bind_address6 =                                                                                                                                                               
lmtp_body_checks =                                                                                                                                                                 
lmtp_cname_overrides_servername = no                                                                                                                                               
lmtp_connect_timeout = 0s                                                                                                                                                          
lmtp_connection_cache_destinations =                                                                                                                                               
lmtp_connection_cache_on_demand = yes                                                                                                                                              
lmtp_connection_cache_time_limit = 2s                                                                                                                                              
lmtp_connection_reuse_count_limit = 0                                                                                                                                              
lmtp_connection_reuse_time_limit = 300s                                                                                                                                            
lmtp_data_done_timeout = 600s                                                                                                                                                      
lmtp_data_init_timeout = 120s                                                                                                                                                      
lmtp_data_xfer_timeout = 180s                                                                                                                                                      
lmtp_defer_if_no_mx_address_found = no                                                                                                                                             
lmtp_delivery_slot_cost = $default_delivery_slot_cost                                                                                                                              
lmtp_delivery_slot_discount = $default_delivery_slot_discount                                                                                                                      
lmtp_delivery_slot_loan = $default_delivery_slot_loan                                                                                                                              
lmtp_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit                                                                            
lmtp_destination_concurrency_limit = $default_destination_concurrency_limit                                                                                                        
lmtp_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback                                                                                
lmtp_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback                                                                                
lmtp_destination_rate_delay = $default_destination_rate_delay                                                                                                                      
lmtp_destination_recipient_limit = $default_destination_recipient_limit                                                                                                            
lmtp_discard_lhlo_keyword_address_maps =                                                                                                                                           
lmtp_discard_lhlo_keywords =                                                                                                                                                       
lmtp_dns_resolver_options =                                                                                                                                                        
lmtp_dns_support_level =                                                                                                                                                           
lmtp_enforce_tls = no                                                                                                                                                              
lmtp_extra_recipient_limit = $default_extra_recipient_limit                                                                                                                        
lmtp_generic_maps =                                                                                                                                                                
lmtp_header_checks =                                                                                                                                                               
lmtp_host_lookup = dns                                                                                                                                                             
lmtp_initial_destination_concurrency = $initial_destination_concurrency                                                                                                            
lmtp_lhlo_name = $myhostname                                                                                                                                                       
lmtp_lhlo_timeout = 300s                                                                                                                                                           
lmtp_line_length_limit = 998                                                                                                                                                       
lmtp_mail_timeout = 300s                                                                                                                                                           
lmtp_mime_header_checks =                                                                                                                                                          
lmtp_minimum_delivery_slots = $default_minimum_delivery_slots                                                                                                                      
lmtp_mx_address_limit = 5                                                                                                                                                          
lmtp_mx_session_limit = 2                                                                                                                                                          
lmtp_nested_header_checks =                                                                                                                                                        
lmtp_per_record_deadline = no                                                                                                                                                      
lmtp_pix_workaround_delay_time = 10s                                                                                                                                               
lmtp_pix_workaround_maps =                                                                                                                                                         
lmtp_pix_workaround_threshold_time = 500s                                                                                                                                          
lmtp_pix_workarounds = disable_esmtp,delay_dotcrlf                                                                                                                                 
lmtp_quit_timeout = 300s                                                                                                                                                           
lmtp_quote_rfc821_envelope = yes                                                                                                                                                   
lmtp_randomize_addresses = yes                                                                                                                                                     
lmtp_rcpt_timeout = 300s                                                                                                                                                           
lmtp_recipient_limit = $default_recipient_limit                                                                                                                                    
lmtp_recipient_refill_delay = $default_recipient_refill_delay                                                                                                                      
lmtp_recipient_refill_limit = $default_recipient_refill_limit                                                                                                                      
lmtp_reply_filter =                                                                                                                                                                
lmtp_rset_timeout = 20s                                                                                                                                                            
lmtp_sasl_auth_cache_name =                                                                                                                                                        
lmtp_sasl_auth_cache_time = 90d                                                                                                                                                    
lmtp_sasl_auth_enable = no                                                                                                                                                         
lmtp_sasl_auth_soft_bounce = yes                                                                                                                                                   
lmtp_sasl_mechanism_filter =                                                                                                                                                       
lmtp_sasl_password_maps =                                                                                                                                                          
lmtp_sasl_path =                                                                                                                                                                   
lmtp_sasl_security_options = noplaintext, noanonymous                                                                                                                              
lmtp_sasl_tls_security_options = $lmtp_sasl_security_options                                                                                                                       
lmtp_sasl_tls_verified_security_options = $lmtp_sasl_tls_security_options                                                                                                          
lmtp_sasl_type = cyrus                                                                                                                                                             
lmtp_send_dummy_mail_auth = no                                                                                                                                                     
lmtp_send_xforward_command = no                                                                                                                                                    
lmtp_sender_dependent_authentication = no                                                                                                                                          
lmtp_skip_5xx_greeting = yes                                                                                                                                                       
lmtp_skip_quit_response = no                                                                                                                                                       
lmtp_starttls_timeout = 300s                                                                                                                                                       
lmtp_tcp_port = 24                                                                                                                                                                 
lmtp_tls_CAfile =                                                                                                                                                                  
lmtp_tls_CApath =                                                                                                                                                                  
lmtp_tls_block_early_mail_reply = no                                                                                                                                               
lmtp_tls_cert_file =                                                                                                                                                               
lmtp_tls_ciphers = medium                                                                                                                                                          
lmtp_tls_dcert_file =                                                                                                                                                              
lmtp_tls_dkey_file = $lmtp_tls_dcert_file                                                                                                                                          
lmtp_tls_eccert_file =                                                                                                                                                             
lmtp_tls_eckey_file = $lmtp_tls_eccert_file                                                                                                                                        
lmtp_tls_enforce_peername = yes                                                                                                                                                    
lmtp_tls_exclude_ciphers =                                                                                                                                                         
lmtp_tls_fingerprint_cert_match =                                                                                                                                                  
lmtp_tls_fingerprint_digest = md5                                                                                                                                                  
lmtp_tls_force_insecure_host_tlsa_lookup = no                                                                                                                                      
lmtp_tls_key_file = $lmtp_tls_cert_file                                                                                                                                            
lmtp_tls_loglevel = 0                                                                                                                                                              
lmtp_tls_mandatory_ciphers = medium                                                                                                                                                
lmtp_tls_mandatory_exclude_ciphers =                                                                                                                                               
lmtp_tls_mandatory_protocols = !SSLv2, !SSLv3                                                                                                                                      
lmtp_tls_note_starttls_offer = no                                                                                                                                                  
lmtp_tls_per_site =                                                                                                                                                                
lmtp_tls_policy_maps =                                                                                                                                                             
lmtp_tls_protocols = !SSLv2, !SSLv3                                                                                                                                                
lmtp_tls_scert_verifydepth = 9                                                                                                                                                     
lmtp_tls_secure_cert_match = nexthop                                                                                                                                               
lmtp_tls_security_level =                                                                                                                                                          
lmtp_tls_session_cache_database =                                                                                                                                                  
lmtp_tls_session_cache_timeout = 3600s                                                                                                                                             
lmtp_tls_trust_anchor_file =                                                                                                                                                       
lmtp_tls_verify_cert_match = hostname                                                                                                                                              
lmtp_use_tls = no                                                                                                                                                                  
lmtp_xforward_timeout = 300s                                                                                                                                                       
lmtps_delivery_slot_cost = $default_delivery_slot_cost                                                                                                                             
lmtps_delivery_slot_discount = $default_delivery_slot_discount                                                                                                                     
lmtps_delivery_slot_loan = $default_delivery_slot_loan                                                                                                                             
lmtps_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit                                                                           
lmtps_destination_concurrency_limit = $default_destination_concurrency_limit                                                                                                       
lmtps_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback                                                                               
lmtps_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback                                                                               
lmtps_destination_rate_delay = $default_destination_rate_delay                                                                                                                     
lmtps_destination_recipient_limit = $default_destination_recipient_limit                                                                                                           
lmtps_extra_recipient_limit = $default_extra_recipient_limit                                                                                                                       
lmtps_initial_destination_concurrency = $initial_destination_concurrency                                                                                                           
lmtps_minimum_delivery_slots = $default_minimum_delivery_slots                                                                                                                     
lmtps_recipient_limit = $default_recipient_limit                                                                                                                                   
lmtps_recipient_refill_delay = $default_recipient_refill_delay                                                                                                                     
lmtps_recipient_refill_limit = $default_recipient_refill_limit                                                                                                                     
local_command_shell =                                                                                                                                                              
local_delivery_slot_cost = $default_delivery_slot_cost                                                                                                                             
local_delivery_slot_discount = $default_delivery_slot_discount                                                                                                                     
local_delivery_slot_loan = $default_delivery_slot_loan                                                                                                                             
local_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit                                                                           
local_destination_concurrency_limit = 2                                                                                                                                            
local_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback                                                                               
local_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback                                                                               
local_destination_rate_delay = $default_destination_rate_delay                                                                                                                     
local_destination_recipient_limit = 1                                                                                                                                              
local_extra_recipient_limit = $default_extra_recipient_limit                                                                                                                       
local_header_rewrite_clients = permit_inet_interfaces                                                                                                                              
local_initial_destination_concurrency = $initial_destination_concurrency                                                                                                           
local_minimum_delivery_slots = $default_minimum_delivery_slots                                                                                                                     
local_recipient_limit = $default_recipient_limit                                                                                                                                   
local_recipient_maps = proxy:unix:passwd.byname $alias_maps                                                                                                                        
local_recipient_refill_delay = $default_recipient_refill_delay                                                                                                                     
local_recipient_refill_limit = $default_recipient_refill_limit                                                                                                                     
local_transport = local:$myhostname                                                                                                                                                
luser_relay =                                                                                                                                                                      
mail_name = Postfix                                                                                                                                                                
mail_owner = postfix                                                                                                                                                               
mail_release_date = 20150720                                                                                                                                                       
mail_spool_directory = /var/mail                                                                                                                                                   
mail_version = 2.11.6                                                                                                                                                              
mailbox_command =                                                                                                                                                                  
mailbox_command_maps =                                                                                                                                                             
mailbox_delivery_lock = fcntl, dotlock                                                                                                                                             
mailbox_size_limit = 51200000                                                                                                                                                      
mailbox_transport =                                                                                                                                                                
mailbox_transport_maps =                                                                                                                                                           
mailq_path = /usr/bin/mailq                                                                                                                                                        
manpage_directory = /usr/local/man                                                                                                                                                 
maps_rbl_domains =                                                                                                                                                                 
maps_rbl_reject_code = 554                                                                                                                                                         
masquerade_classes = envelope_sender, header_sender, header_recipient                                                                                                              
masquerade_domains =                                                                                                                                                               
masquerade_exceptions =                                                                                                                                                            
master_service_disable =                                                                                                                                                           
max_idle = 100s                                                                                                                                                                    
max_use = 100                                                                                                                                                                      
maximal_backoff_time = 4000s                                                                                                                                                       
maximal_queue_lifetime = 5d                                                                                                                                                        
message_reject_characters =                                                                                                                                                        
message_size_limit = 10240000                                                                                                                                                      
message_strip_characters =                                                                                                                                                         
milter_command_timeout = 30s                                                                                                                                                       
milter_connect_macros = j {daemon_name} v                                                                                                                                          
milter_connect_timeout = 30s                                                                                                                                                       
milter_content_timeout = 300s                                                                                                                                                      
milter_data_macros = i                                                                                                                                                             
milter_default_action = tempfail                                                                                                                                                   
milter_end_of_data_macros = i                                                                                                                                                      
milter_end_of_header_macros = i                                                                                                                                                    
milter_header_checks =                                                                                                                                                             
milter_helo_macros = {tls_version} {cipher} {cipher_bits} {cert_subject} {cert_issuer}                                                                                             
milter_macro_daemon_name = $myhostname                                                                                                                                             
milter_macro_v = $mail_name $mail_version                                                                                                                                          
milter_mail_macros = i {auth_type} {auth_authen} {auth_author} {mail_addr} {mail_host} {mail_mailer}                                                                               
milter_protocol = 6                                                                                                                                                                
milter_rcpt_macros = i {rcpt_addr} {rcpt_host} {rcpt_mailer}                                                                                                                       
milter_unknown_command_macros =                                                                                                                                                    
mime_boundary_length_limit = 2048                                                                                                                                                  
mime_header_checks = $header_checks                                                                                                                                                
mime_nesting_limit = 100                                                                                                                                                           
minimal_backoff_time = 300s                                                                                                                                                        
multi_instance_directories =                                                                                                                                                       
multi_instance_enable = no                                                                                                                                                         
multi_instance_group =                                                                                                                                                             
multi_instance_name =                                                                                                                                                              
multi_instance_wrapper =                                                                                                                                                           
multi_recipient_bounce_reject_code = 550                                                                                                                                           
mydestination = $myhostname, localhost.$mydomain, localhost                                                                                                                        
mydomain = dmz.nausch.org                                                                                                                                                          
myhostname = vml000087.dmz.nausch.org                                                                                                                                              
mynetworks = 127.0.0.0/8 10.0.0.0/24 [::1]/128 [fe80::]/64                                                                                                                         
mynetworks_style = subnet                                                                                                                                                          
myorigin = $myhostname                                                                                                                                                             
nested_header_checks = $header_checks                                                                                                                                              
newaliases_path = /usr/bin/newaliases                                                                                                                                              
non_fqdn_reject_code = 504                                                                                                                                                         
non_smtpd_milters =                                                                                                                                                                
notify_classes = resource, software                                                                                                                                                
owner_request_special = yes                                                                                                                                                        
parent_domain_matches_subdomains = debug_peer_list,fast_flush_domains,mynetworks,permit_mx_backup_networks,qmqpd_authorized_clients,relay_domains,smtpd_access_maps                
permit_mx_backup_networks =                                                                                                                                                        
pickup_service_name = pickup                                                                                                                                                       
plaintext_reject_code = 450                                                                                                                                                        
postmulti_control_commands = reload flush                                                                                                                                          
postmulti_start_commands = start                                                                                                                                                   
postmulti_stop_commands = stop abort drain quick-stop                                                                                                                              
postscreen_access_list = permit_mynetworks                                                                                                                                         
postscreen_bare_newline_action = ignore                                                                                                                                            
postscreen_bare_newline_enable = no                                                                                                                                                
postscreen_bare_newline_ttl = 30d                                                                                                                                                  
postscreen_blacklist_action = ignore                                                                                                                                               
postscreen_cache_cleanup_interval = 12h                                                                                                                                            
postscreen_cache_map = btree:$data_directory/postscreen_cache                                                                                                                      
postscreen_cache_retention_time = 7d                                                                                                                                               
postscreen_client_connection_count_limit = $smtpd_client_connection_count_limit                                                                                                    
postscreen_command_count_limit = 20                                                                                                                                                
postscreen_command_filter =                                                                                                                                                        
postscreen_command_time_limit = ${stress?10}${stress:300}s                                                                                                                         
postscreen_disable_vrfy_command = $disable_vrfy_command                                                                                                                            
postscreen_discard_ehlo_keyword_address_maps = $smtpd_discard_ehlo_keyword_address_maps                                                                                            
postscreen_discard_ehlo_keywords = $smtpd_discard_ehlo_keywords                                                                                                                    
postscreen_dnsbl_action = ignore                                                                                                                                                   
postscreen_dnsbl_reply_map =                                                                                                                                                       
postscreen_dnsbl_sites =                                                                                                                                                           
postscreen_dnsbl_threshold = 1                                                                                                                                                     
postscreen_dnsbl_ttl = 1h                                                                                                                                                          
postscreen_dnsbl_whitelist_threshold = 0                                                                                                                                           
postscreen_enforce_tls = $smtpd_enforce_tls                                                                                                                                        
postscreen_expansion_filter = $smtpd_expansion_filter                                                                                                                              
postscreen_forbidden_commands = $smtpd_forbidden_commands                                                                                                                          
postscreen_greet_action = ignore                                                                                                                                                   
postscreen_greet_banner = $smtpd_banner                                                                                                                                            
postscreen_greet_ttl = 1d                                                                                                                                                          
postscreen_greet_wait = ${stress?2}${stress:6}s                                                                                                                                    
postscreen_helo_required = $smtpd_helo_required                                                                                                                                    
postscreen_non_smtp_command_action = drop                                                                                                                                          
postscreen_non_smtp_command_enable = no                                                                                                                                            
postscreen_non_smtp_command_ttl = 30d                                                                                                                                              
postscreen_pipelining_action = enforce                                                                                                                                             
postscreen_pipelining_enable = no                                                                                                                                                  
postscreen_pipelining_ttl = 30d                                                                                                                                                    
postscreen_post_queue_limit = $default_process_limit                                                                                                                               
postscreen_pre_queue_limit = $default_process_limit                                                                                                                                
postscreen_reject_footer = $smtpd_reject_footer                                                                                                                                    
postscreen_tls_security_level = $smtpd_tls_security_level                                                                                                                          
postscreen_upstream_proxy_protocol =                                                                                                                                               
postscreen_upstream_proxy_timeout = 5s                                                                                                                                             
postscreen_use_tls = $smtpd_use_tls                                                                                                                                                
postscreen_watchdog_timeout = 10s                                                                                                                                                  
postscreen_whitelist_interfaces = static:all                                                                                                                                       
prepend_delivered_header = command, file, forward                                                                                                                                  
process_id = 10682                                                                                                                                                                 
process_id_directory = pid                                                                                                                                                         
process_name = postconf                                                                                                                                                            
propagate_unmatched_extensions = canonical, virtual                                                                                                                                
proxy_interfaces =                                                                                                                                                                 
proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks $smtpd_sender_login_maps $sender_bcc_maps $recipient_bcc_maps $smtp_generic_maps $lmtp_generic_maps $alias_maps                                                                                                                                       
proxy_write_maps = $smtp_sasl_auth_cache_name $lmtp_sasl_auth_cache_name $address_verify_map $postscreen_cache_map                                                                 
proxymap_service_name = proxymap                                                                                                                                                   
proxywrite_service_name = proxywrite                                                                                                                                               
qmgr_clog_warn_time = 300s                                                                                                                                                         
qmgr_daemon_timeout = 1000s                                                                                                                                                        
qmgr_fudge_factor = 100                                                                                                                                                            
qmgr_ipc_timeout = 60s                                                                                                                                                             
qmgr_message_active_limit = 20000                                                                                                                                                  
qmgr_message_recipient_limit = 20000                                                                                                                                               
qmgr_message_recipient_minimum = 10                                                                                                                                                
qmqpd_authorized_clients =                                                                                                                                                         
qmqpd_client_port_logging = no                                                                                                                                                     
qmqpd_error_delay = 1s                                                                                                                                                             
qmqpd_timeout = 300s                                                                                                                                                               
queue_directory = /var/spool/postfix                                                                                                                                               
queue_file_attribute_count_limit = 100                                                                                                                                             
queue_minfree = 0                                                                                                                                                                  
queue_run_delay = 300s                                                                                                                                                             
queue_service_name = qmgr                                                                                                                                                          
rbl_reply_maps =                                                                                                                                                                   
readme_directory = no                                                                                                                                                              
receive_override_options =                                                                                                                                                         
recipient_bcc_maps =                                                                                                                                                               
recipient_canonical_classes = envelope_recipient, header_recipient                                                                                                                 
recipient_canonical_maps =                                                                                                                                                         
recipient_delimiter =                                                                                                                                                              
reject_code = 554                                                                                                                                                                  
reject_tempfail_action = defer_if_permit                                                                                                                                           
relay_clientcerts =                                                                                                                                                                
relay_delivery_slot_cost = $default_delivery_slot_cost                                                                                                                             
relay_delivery_slot_discount = $default_delivery_slot_discount                                                                                                                     
relay_delivery_slot_loan = $default_delivery_slot_loan                                                                                                                             
relay_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit                                                                           
relay_destination_concurrency_limit = $default_destination_concurrency_limit                                                                                                       
relay_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback                                                                               
relay_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback                                                                               
relay_destination_rate_delay = $default_destination_rate_delay                                                                                                                     
relay_destination_recipient_limit = $default_destination_recipient_limit                                                                                                           
relay_domains = $mydestination                                                                                                                                                     
relay_domains_reject_code = 554                                                                                                                                                    
relay_extra_recipient_limit = $default_extra_recipient_limit                                                                                                                       
relay_initial_destination_concurrency = $initial_destination_concurrency                                                                                                           
relay_minimum_delivery_slots = $default_minimum_delivery_slots                                                                                                                     
relay_recipient_limit = $default_recipient_limit                                                                                                                                   
relay_recipient_maps =                                                                                                                                                             
relay_recipient_refill_delay = $default_recipient_refill_delay                                                                                                                     
relay_recipient_refill_limit = $default_recipient_refill_limit                                                                                                                     
relay_transport = relay                                                                                                                                                            
relayhost =                                                                                                                                                                        
relocated_maps =                                                                                                                                                                   
remote_header_rewrite_domain =                                                                                                                                                     
require_home_directory = no                                                                                                                                                        
reset_owner_alias = no                                                                                                                                                             
resolve_dequoted_address = yes                                                                                                                                                     
resolve_null_domain = no                                                                                                                                                           
resolve_numeric_domain = no                                                                                                                                                        
retry_delivery_slot_cost = $default_delivery_slot_cost                                                                                                                             
retry_delivery_slot_discount = $default_delivery_slot_discount                                                                                                                     
retry_delivery_slot_loan = $default_delivery_slot_loan                                                                                                                             
retry_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit                                                                           
retry_destination_concurrency_limit = $default_destination_concurrency_limit                                                                                                       
retry_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback                                                                               
retry_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback                                                                               
retry_destination_rate_delay = $default_destination_rate_delay                                                                                                                     
retry_destination_recipient_limit = $default_destination_recipient_limit                                                                                                           
retry_extra_recipient_limit = $default_extra_recipient_limit                                                                                                                       
retry_initial_destination_concurrency = $initial_destination_concurrency                                                                                                           
retry_minimum_delivery_slots = $default_minimum_delivery_slots                                                                                                                     
retry_recipient_limit = $default_recipient_limit                                                                                                                                   
retry_recipient_refill_delay = $default_recipient_refill_delay                                                                                                                     
retry_recipient_refill_limit = $default_recipient_refill_limit                                                                                                                     
rewrite_service_name = rewrite                                                                                                                                                     
sample_directory = /etc/postfix                                                                                                                                                    
send_cyrus_sasl_authzid = no                                                                                                                                                       
sender_bcc_maps =                                                                                                                                                                  
sender_canonical_classes = envelope_sender, header_sender                                                                                                                          
sender_canonical_maps =                                                                                                                                                            
sender_dependent_default_transport_maps =                                                                                                                                          
sender_dependent_relayhost_maps =                                                                                                                                                  
sendmail_fix_line_endings = always                                                                                                                                                 
sendmail_path = /usr/sbin/sendmail                                                                                                                                                 
service_throttle_time = 60s                                                                                                                                                        
setgid_group = postdrop                                                                                                                                                            
show_user_unknown_table_name = yes                                                                                                                                                 
showq_service_name = showq                                                                                                                                                         
smtp_address_preference = any                                                                                                                                                      
smtp_always_send_ehlo = yes                                                                                                                                                        
smtp_bind_address =                                                                                                                                                                
smtp_bind_address6 =                                                                                                                                                               
smtp_body_checks =                                                                                                                                                                 
smtp_cname_overrides_servername = no                                                                                                                                               
smtp_connect_timeout = 30s                                                                                                                                                         
smtp_connection_cache_destinations =                                                                                                                                               
smtp_connection_cache_on_demand = yes                                                                                                                                              
smtp_connection_cache_time_limit = 2s                                                                                                                                              
smtp_connection_reuse_count_limit = 0                                                                                                                                              
smtp_connection_reuse_time_limit = 300s                                                                                                                                            
smtp_data_done_timeout = 600s                                                                                                                                                      
smtp_data_init_timeout = 120s                                                                                                                                                      
smtp_data_xfer_timeout = 180s                                                                                                                                                      
smtp_defer_if_no_mx_address_found = no                                                                                                                                             
smtp_delivery_slot_cost = $default_delivery_slot_cost                                                                                                                              
smtp_delivery_slot_discount = $default_delivery_slot_discount                                                                                                                      
smtp_delivery_slot_loan = $default_delivery_slot_loan                                                                                                                              
smtp_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit                                                                            
smtp_destination_concurrency_limit = $default_destination_concurrency_limit                                                                                                        
smtp_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback                                                                                
smtp_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback                                                                                
smtp_destination_rate_delay = $default_destination_rate_delay                                                                                                                      
smtp_destination_recipient_limit = $default_destination_recipient_limit                                                                                                            
smtp_discard_ehlo_keyword_address_maps =                                                                                                                                           
smtp_discard_ehlo_keywords =                                                                                                                                                       
smtp_dns_resolver_options =                                                                                                                                                        
smtp_dns_support_level =                                                                                                                                                           
smtp_enforce_tls = no                                                                                                                                                              
smtp_extra_recipient_limit = $default_extra_recipient_limit                                                                                                                        
smtp_fallback_relay = $fallback_relay                                                                                                                                              
smtp_generic_maps =                                                                                                                                                                
smtp_header_checks =                                                                                                                                                               
smtp_helo_name = $myhostname                                                                                                                                                       
smtp_helo_timeout = 300s                                                                                                                                                           
smtp_host_lookup = dns                                                                                                                                                             
smtp_initial_destination_concurrency = $initial_destination_concurrency                                                                                                            
smtp_line_length_limit = 998                                                                                                                                                       
smtp_mail_timeout = 300s                                                                                                                                                           
smtp_mime_header_checks =                                                                                                                                                          
smtp_minimum_delivery_slots = $default_minimum_delivery_slots                                                                                                                      
smtp_mx_address_limit = 5                                                                                                                                                          
smtp_mx_session_limit = 2                                                                                                                                                          
smtp_nested_header_checks =                                                                                                                                                        
smtp_never_send_ehlo = no                                                                                                                                                          
smtp_per_record_deadline = no                                                                                                                                                      
smtp_pix_workaround_delay_time = 10s                                                                                                                                               
smtp_pix_workaround_maps =                                                                                                                                                         
smtp_pix_workaround_threshold_time = 500s                                                                                                                                          
smtp_pix_workarounds = disable_esmtp,delay_dotcrlf                                                                                                                                 
smtp_quit_timeout = 300s                                                                                                                                                           
smtp_quote_rfc821_envelope = yes                                                                                                                                                   
smtp_randomize_addresses = yes                                                                                                                                                     
smtp_rcpt_timeout = 300s                                                                                                                                                           
smtp_recipient_limit = $default_recipient_limit                                                                                                                                    
smtp_recipient_refill_delay = $default_recipient_refill_delay                                                                                                                      
smtp_recipient_refill_limit = $default_recipient_refill_limit                                                                                                                      
smtp_reply_filter =                                                                                                                                                                
smtp_rset_timeout = 20s                                                                                                                                                            
smtp_sasl_auth_cache_name =                                                                                                                                                        
smtp_sasl_auth_cache_time = 90d                                                                                                                                                    
smtp_sasl_auth_enable = no                                                                                                                                                         
smtp_sasl_auth_soft_bounce = yes                                                                                                                                                   
smtp_sasl_mechanism_filter =                                                                                                                                                       
smtp_sasl_password_maps =                                                                                                                                                          
smtp_sasl_path =                                                                                                                                                                   
smtp_sasl_security_options = noplaintext, noanonymous                                                                                                                              
smtp_sasl_tls_security_options = $smtp_sasl_security_options                                                                                                                       
smtp_sasl_tls_verified_security_options = $smtp_sasl_tls_security_options                                                                                                          
smtp_sasl_type = cyrus                                                                                                                                                             
smtp_send_dummy_mail_auth = no                                                                                                                                                     
smtp_send_xforward_command = no                                                                                                                                                    
smtp_sender_dependent_authentication = no                                                                                                                                          
smtp_skip_5xx_greeting = yes                                                                                                                                                       
smtp_skip_quit_response = yes                                                                                                                                                      
smtp_starttls_timeout = 300s                                                                                                                                                       
smtp_tls_CAfile =                                                                                                                                                                  
smtp_tls_CApath =                                                                                                                                                                  
smtp_tls_block_early_mail_reply = no                                                                                                                                               
smtp_tls_cert_file =                                                                                                                                                               
smtp_tls_ciphers = medium                                                                                                                                                          
smtp_tls_dcert_file =                                                                                                                                                              
smtp_tls_dkey_file = $smtp_tls_dcert_file                                                                                                                                          
smtp_tls_eccert_file =                                                                                                                                                             
smtp_tls_eckey_file = $smtp_tls_eccert_file                                                                                                                                        
smtp_tls_enforce_peername = yes                                                                                                                                                    
smtp_tls_exclude_ciphers =                                                                                                                                                         
smtp_tls_fingerprint_cert_match =                                                                                                                                                  
smtp_tls_fingerprint_digest = md5                                                                                                                                                  
smtp_tls_force_insecure_host_tlsa_lookup = no                                                                                                                                      
smtp_tls_key_file = $smtp_tls_cert_file                                                                                                                                            
smtp_tls_loglevel = 0                                                                                                                                                              
smtp_tls_mandatory_ciphers = medium                                                                                                                                                
smtp_tls_mandatory_exclude_ciphers =                                                                                                                                               
smtp_tls_mandatory_protocols = !SSLv2, !SSLv3                                                                                                                                      
smtp_tls_note_starttls_offer = no                                                                                                                                                  
smtp_tls_per_site =                                                                                                                                                                
smtp_tls_policy_maps =                                                                                                                                                             
smtp_tls_protocols = !SSLv2, !SSLv3                                                                                                                                                
smtp_tls_scert_verifydepth = 9                                                                                                                                                     
smtp_tls_secure_cert_match = nexthop, dot-nexthop                                                                                                                                  
smtp_tls_security_level =                                                                                                                                                          
smtp_tls_session_cache_database =                                                                                                                                                  
smtp_tls_session_cache_timeout = 3600s                                                                                                                                             
smtp_tls_trust_anchor_file =                                                                                                                                                       
smtp_tls_verify_cert_match = hostname                                                                                                                                              
smtp_use_tls = no                                                                                                                                                                  
smtp_xforward_timeout = 300s                                                                                                                                                       
smtpd_authorized_verp_clients = $authorized_verp_clients                                                                                                                           
smtpd_authorized_xclient_hosts =                                                                                                                                                   
smtpd_authorized_xforward_hosts =                                                                                                                                                  
smtpd_banner = $myhostname ESMTP $mail_name                                                                                                                                        
smtpd_client_connection_count_limit = 50                                                                                                                                           
smtpd_client_connection_rate_limit = 0                                                                                                                                             
smtpd_client_event_limit_exceptions = ${smtpd_client_connection_limit_exceptions:$mynetworks}                                                                                      
smtpd_client_message_rate_limit = 0                                                                                                                                                
smtpd_client_new_tls_session_rate_limit = 0                                                                                                                                        
smtpd_client_port_logging = no                                                                                                                                                     
smtpd_client_recipient_rate_limit = 0                                                                                                                                              
smtpd_client_restrictions =                                                                                                                                                        
smtpd_command_filter =                                                                                                                                                             
smtpd_data_restrictions =                                                                                                                                                          
smtpd_delay_open_until_valid_rcpt = yes                                                                                                                                            
smtpd_delay_reject = yes                                                                                                                                                           
smtpd_discard_ehlo_keyword_address_maps =                                                                                                                                          
smtpd_discard_ehlo_keywords =                                                                                                                                                      
smtpd_end_of_data_restrictions =                                                                                                                                                   
smtpd_enforce_tls = no                                                                                                                                                             
smtpd_error_sleep_time = 1s                                                                                                                                                        
smtpd_etrn_restrictions =                                                                                                                                                          
smtpd_expansion_filter = \t\40!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~                                                      
smtpd_forbidden_commands = CONNECT GET POST                                                                                                                                        
smtpd_hard_error_limit = ${stress?1}${stress:20}                                                                                                                                   
smtpd_helo_required = no                                                                                                                                                           
smtpd_helo_restrictions =                                                                                                                                                          
smtpd_history_flush_threshold = 100                                                                                                                                                
smtpd_junk_command_limit = ${stress?1}${stress:100}                                                                                                                                
smtpd_log_access_permit_actions =                                                                                                                                                  
smtpd_milters =                                                                                                                                                                    
smtpd_noop_commands =                                                                                                                                                              
smtpd_null_access_lookup_key = <>                                                                                                                                                  
smtpd_peername_lookup = yes                                                                                                                                                        
smtpd_per_record_deadline = ${stress?yes}${stress:no}                                                                                                                              
smtpd_policy_service_max_idle = 300s                                                                                                                                               
smtpd_policy_service_max_ttl = 1000s                                                                                                                                               
smtpd_policy_service_timeout = 100s                                                                                                                                                
smtpd_proxy_ehlo = $myhostname                                                                                                                                                     
smtpd_proxy_filter =                                                                                                                                                               
smtpd_proxy_options =                                                                                                                                                              
smtpd_proxy_timeout = 100s                                                                                                                                                         
smtpd_recipient_limit = 1000                                                                                                                                                       
smtpd_recipient_overshoot_limit = 1000                                                                                                                                             
smtpd_recipient_restrictions =                                                                                                                                                     
smtpd_reject_footer =                                                                                                                                                              
smtpd_reject_unlisted_recipient = yes                                                                                                                                              
smtpd_reject_unlisted_sender = no                                                                                                                                                  
smtpd_relay_restrictions = permit_mynetworks, permit_sasl_authenticated, defer_unauth_destination                                                                                  
smtpd_restriction_classes =                                                                                                                                                        
smtpd_sasl_auth_enable = no                                                                                                                                                        
smtpd_sasl_authenticated_header = no                                                                                                                                               
smtpd_sasl_exceptions_networks =                                                                                                                                                   
smtpd_sasl_local_domain =                                                                                                                                                          
smtpd_sasl_path = smtpd                                                                                                                                                            
smtpd_sasl_security_options = noanonymous                                                                                                                                          
smtpd_sasl_service = smtp                                                                                                                                                          
smtpd_sasl_tls_security_options = $smtpd_sasl_security_options                                                                                                                     
smtpd_sasl_type = cyrus                                                                                                                                                            
smtpd_sender_login_maps =                                                                                                                                                          
smtpd_sender_restrictions =                                                                                                                                                        
smtpd_service_name = smtpd                                                                                                                                                         
smtpd_soft_error_limit = 10                                                                                                                                                        
smtpd_starttls_timeout = ${stress?10}${stress:300}s                                                                                                                                
smtpd_timeout = ${stress?10}${stress:300}s                                                                                                                                         
smtpd_tls_CAfile =                                                                                                                                                                 
smtpd_tls_CApath =                                                                                                                                                                 
smtpd_tls_always_issue_session_ids = yes                                                                                                                                           
smtpd_tls_ask_ccert = no                                                                                                                                                           
smtpd_tls_auth_only = no                                                                                                                                                           
smtpd_tls_ccert_verifydepth = 9                                                                                                                                                    
smtpd_tls_cert_file =                                                                                                                                                              
smtpd_tls_ciphers = medium                                                                                                                                                         
smtpd_tls_dcert_file =                                                                                                                                                             
smtpd_tls_dh1024_param_file =                                                                                                                                                      
smtpd_tls_dh512_param_file =                                                                                                                                                       
smtpd_tls_dkey_file = $smtpd_tls_dcert_file                                                                                                                                        
smtpd_tls_eccert_file =                                                                                                                                                            
smtpd_tls_eckey_file = $smtpd_tls_eccert_file                                                                                                                                      
smtpd_tls_eecdh_grade = strong                                                                                                                                                     
smtpd_tls_exclude_ciphers =                                                                                                                                                        
smtpd_tls_fingerprint_digest = md5                                                                                                                                                 
smtpd_tls_key_file = $smtpd_tls_cert_file                                                                                                                                          
smtpd_tls_loglevel = 0                                                                                                                                                             
smtpd_tls_mandatory_ciphers = medium                                                                                                                                               
smtpd_tls_mandatory_exclude_ciphers =                                                                                                                                              
smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3                                                                                                                                     
smtpd_tls_protocols = !SSLv2, !SSLv3                                                                                                                                               
smtpd_tls_received_header = no                                                                                                                                                     
smtpd_tls_req_ccert = no                                                                                                                                                           
smtpd_tls_security_level =                                                                                                                                                         
smtpd_tls_session_cache_database =                                                                                                                                                 
smtpd_tls_session_cache_timeout = 3600s                                                                                                                                            
smtpd_tls_wrappermode = no                                                                                                                                                         
smtpd_upstream_proxy_protocol =                                                                                                                                                    
smtpd_upstream_proxy_timeout = 5s                                                                                                                                                  
smtpd_use_tls = no                                                                                                                                                                 
soft_bounce = no                                                                                                                                                                   
stale_lock_time = 500s                                                                                                                                                             
stress =                                                                                                                                                                           
strict_7bit_headers = no                                                                                                                                                           
strict_8bitmime = no                                                                                                                                                               
strict_8bitmime_body = no                                                                                                                                                          
strict_mailbox_ownership = yes                                                                                                                                                     
strict_mime_encoding_domain = no                                                                                                                                                   
strict_rfc821_envelopes = no                                                                                                                                                       
sun_mailtool_compatibility = no                                                                                                                                                    
swap_bangpath = yes                                                                                                                                                                
syslog_facility = mail                                                                                                                                                             
syslog_name = ${multi_instance_name:postfix}${multi_instance_name?$multi_instance_name}                                                                                            
tcp_windowsize = 0                                                                                                                                                                 
tls_append_default_CA = no                                                                                                                                                         
tls_daemon_random_bytes = 32                                                                                                                                                       
tls_dane_digest_agility = on                                                                                                                                                       
tls_dane_digests = sha512 sha256                                                                                                                                                   
tls_dane_trust_anchor_digest_enable = yes                                                                                                                                          
tls_disable_workarounds =                                                                                                                                                          
tls_eecdh_strong_curve = prime256v1                                                                                                                                                
tls_eecdh_ultra_curve = secp384r1                                                                                                                                                  
tls_export_cipherlist = aNULL:-aNULL:ALL:+RC4:@STRENGTH                                                                                                                            
tls_high_cipherlist = aNULL:-aNULL:ALL:!EXPORT:!LOW:!MEDIUM:+RC4:@STRENGTH                                                                                                         
tls_legacy_public_key_fingerprints = no                                                                                                                                            
tls_low_cipherlist = aNULL:-aNULL:ALL:!EXPORT:+RC4:@STRENGTH                                                                                                                       
tls_medium_cipherlist = aNULL:-aNULL:ALL:!EXPORT:!LOW:+RC4:@STRENGTH                                                                                                               
tls_null_cipherlist = eNULL:!aNULL                                                                                                                                                 
tls_preempt_cipherlist = no                                                                                                                                                        
tls_random_bytes = 32                                                                                                                                                              
tls_random_exchange_name = ${data_directory}/prng_exch                                                                                                                             
tls_random_prng_update_period = 3600s                                                                                                                                              
tls_random_reseed_period = 3600s                                                                                                                                                   
tls_random_source = dev:/dev/urandom                                                                                                                                               
tls_ssl_options =                                                                                                                                                                  
tls_wildcard_matches_multiple_labels = yes                                                                                                                                         
tlsmgr_service_name = tlsmgr                                                                                                                                                       
tlsproxy_enforce_tls = $smtpd_enforce_tls                                                                                                                                          
tlsproxy_service_name = tlsproxy                                                                                                                                                   
tlsproxy_tls_CAfile = $smtpd_tls_CAfile                                                                                                                                            
tlsproxy_tls_CApath = $smtpd_tls_CApath                                                                                                                                            
tlsproxy_tls_always_issue_session_ids = $smtpd_tls_always_issue_session_ids                                                                                                        
tlsproxy_tls_ask_ccert = $smtpd_tls_ask_ccert                                                                                                                                      
tlsproxy_tls_ccert_verifydepth = $smtpd_tls_ccert_verifydepth                                                                                                                      
tlsproxy_tls_cert_file = $smtpd_tls_cert_file                                                                                                                                      
tlsproxy_tls_ciphers = $smtpd_tls_ciphers                                                                                                                                          
tlsproxy_tls_dcert_file = $smtpd_tls_dcert_file                                                                                                                                    
tlsproxy_tls_dh1024_param_file = $smtpd_tls_dh1024_param_file                                                                                                                      
tlsproxy_tls_dh512_param_file = $smtpd_tls_dh512_param_file                                                                                                                        
tlsproxy_tls_dkey_file = $smtpd_tls_dkey_file                                                                                                                                      
tlsproxy_tls_eccert_file = $smtpd_tls_eccert_file                                                                                                                                  
tlsproxy_tls_eckey_file = $smtpd_tls_eckey_file                                                                                                                                    
tlsproxy_tls_eecdh_grade = $smtpd_tls_eecdh_grade                                                                                                                                  
tlsproxy_tls_exclude_ciphers = $smtpd_tls_exclude_ciphers                                                                                                                          
tlsproxy_tls_fingerprint_digest = $smtpd_tls_fingerprint_digest                                                                                                                    
tlsproxy_tls_key_file = $smtpd_tls_key_file                                                                                                                                        
tlsproxy_tls_loglevel = $smtpd_tls_loglevel                                                                                                                                        
tlsproxy_tls_mandatory_ciphers = $smtpd_tls_mandatory_ciphers
tlsproxy_tls_mandatory_exclude_ciphers = $smtpd_tls_mandatory_exclude_ciphers
tlsproxy_tls_mandatory_protocols = $smtpd_tls_mandatory_protocols
tlsproxy_tls_protocols = $smtpd_tls_protocols
tlsproxy_tls_req_ccert = $smtpd_tls_req_ccert
tlsproxy_tls_security_level = $smtpd_tls_security_level
tlsproxy_use_tls = $smtpd_use_tls
tlsproxy_watchdog_timeout = 10s
trace_service_name = trace
transport_maps =
transport_retry_time = 60s
trigger_timeout = 10s
undisclosed_recipients_header =
unknown_address_reject_code = 450
unknown_address_tempfail_action = $reject_tempfail_action
unknown_client_reject_code = 450
unknown_helo_hostname_tempfail_action = $reject_tempfail_action
unknown_hostname_reject_code = 450
unknown_local_recipient_reject_code = 550
unknown_relay_recipient_reject_code = 550
unknown_virtual_alias_reject_code = 550
unknown_virtual_mailbox_reject_code = 550
unverified_recipient_defer_code = 450
unverified_recipient_reject_code = 450
unverified_recipient_reject_reason =
unverified_recipient_tempfail_action = $reject_tempfail_action
unverified_sender_defer_code = 450
unverified_sender_reject_code = 450
unverified_sender_reject_reason =
unverified_sender_tempfail_action = $reject_tempfail_action
verp_delimiter_filter = -=+
virtual_alias_domains = $virtual_alias_maps
virtual_alias_expansion_limit = 1000
virtual_alias_maps = $virtual_maps
virtual_alias_recursion_limit = 1000
virtual_delivery_slot_cost = $default_delivery_slot_cost
virtual_delivery_slot_discount = $default_delivery_slot_discount
virtual_delivery_slot_loan = $default_delivery_slot_loan
virtual_destination_concurrency_failed_cohort_limit = $default_destination_concurrency_failed_cohort_limit
virtual_destination_concurrency_limit = $default_destination_concurrency_limit
virtual_destination_concurrency_negative_feedback = $default_destination_concurrency_negative_feedback
virtual_destination_concurrency_positive_feedback = $default_destination_concurrency_positive_feedback
virtual_destination_rate_delay = $default_destination_rate_delay
virtual_destination_recipient_limit = $default_destination_recipient_limit
virtual_extra_recipient_limit = $default_extra_recipient_limit
virtual_gid_maps =
virtual_initial_destination_concurrency = $initial_destination_concurrency
virtual_mailbox_base =
virtual_mailbox_domains = $virtual_mailbox_maps
virtual_mailbox_limit = 51200000
virtual_mailbox_lock = fcntl, dotlock
virtual_mailbox_maps =
virtual_minimum_delivery_slots = $default_minimum_delivery_slots
virtual_minimum_uid = 100
virtual_recipient_limit = $default_recipient_limit
virtual_recipient_refill_delay = $default_recipient_refill_delay
virtual_recipient_refill_limit = $default_recipient_refill_limit
virtual_transport = virtual
virtual_uid_maps =

Möchten wir nun einen einzelne Variable abfragen, die nicht den Defaultvorgaben entspricht benutzen wir im Fall von myorigin den folgenden Aufruf.

 # postconf -d myorigin
 myorigin = $myhostname

Wollen wir einen Parameter ändern, so benutzen wir die Option -e. Als erstes fragen wir den wert einer Variable, im folgenden Beispiel von smtpd_client_connection_count_limit.

 # postconf -d smtpd_client_connection_count_limit
 smtpd_client_connection_count_limit = 50

Den Defaulwert von 50 ändern wir nun ab auf den Wert 10.

 # postconf -e "smtpd_client_connection_count_limit = 25"

Anschließend muss via systemctl reload postfix der laufende Daemon noch von der Änderung an der main.cf informiert werden.

Auf die wichtigsten Konfigurationsparameter für den Betrieb unseres Mailservers gehen wir nun kurz ein:

  • myhostname
    Definition des Hostnames, über den der Mailserver später erreichbar sein wird. Die IP-Adresse des Mailservers muss später auch reverse auf gelöst werden könnne und dem hier definiertem Hostnamen entsprechen.
  • mydomain
    Definition der eigenen Domäne. Normalerweise, wird man diesen Wert nie setzen müssen, da der Wert automatisch vom Parameter myhostname abgeleitet wird, in dem der Host-Teil abgetrennt wird. Aus myhostname = mx1.nausch.org wird so nausch.org, ohne dasss wir extra Hand anlegen müssen. Den Parameter mydomain wird man also nur setzen müssen, wenn der Wert vom Domain-Teil des Parameters myhostname abweicht!
  • mydestination Über diesen Parameter wird definiert, für welche Domains sich unser Postfix als final destination fühlt; der MTA also eigentlich eMails annehmen soll. Normalerweise wird dies neben dem Wert localhost der Domain und Hostname des Servers sein.
    Der Parameter mydestination beschreibt nur den realen Hostnamen sowie der realen Domäne des Mailservers. Möchte man virtuelle Domänen verwenden, definiert man diese mit Hilfe der virtual-table und nicht bei mydestination!
  • myorigin Werden eMails lokal auf dem Mailserverhost generiert, erzeugt Postfix „richtige eMAiladressen“, in dem der Mailserver den User-Namen bzw. die User-ID mit dem Wert aus $myorigin ergänzt. Der Defaultwert myorigin = $mydomain bewirkt also, dass eine eMail von root auf unserem Host mx1.nausch.org die eMailadresse root@nausch.org erhält. Möchte man z.B. für DMZ-interne eMails in der eMailadresse direkt den Hostnamen mit angeben, so wird man hier statt $mydomain $myhostname angeben; somit würde dann die Adresse logwatch@pml010043.intra.nausch.org statt logwatch@nausch.org generiert.
  • mynetworks
    Muss man mehrere verschiedene Netzbereiche, oder einzelne Hosts zum sicheren Relayen freischalten, dann müssen die einzelnen Netzbereiche, bzw. Hosts über den Parameter mynetworks definiert werden. 10.10.10.0/24 beschreibt so ein ganzes Netz, 10.0.0.10/32 hingegen nur einen einzelnen Host.
  • mynetworks_style
    Festlegung des Netzes oder des Netzbereiches, die unser Postfix als vertrauenswürdig betrachten soll. Host aus diesem Netzbereichen ist es gestattet, eMails an externe Empfänger einzuliefern, die unser MTA dann wiederum ausliefern wird. class, host und subnet (Defaulteinstellung) können hier ausgewählt werden.
  • inet_interfaces
    Festlegung der Netzwerk-Adresse, von denen der Mailserver Verbindungen annehmen soll. Bei einfachen Workstations wird man hier den Vorgabewert localhost belassen. Wollen wir einen richtigen Mailserver betreiben, so definieren wir hier entweder direkt sine IP-Adresse, oder geben das Schlüsselwort all für alle Netzwerkschnittstellen an.
  • inet_protocols
    Festlegung des verwendeten Internetprotokolles, abhängig von der Serverkonfiguration selbst. Wurde der IPv6-Support deaktiviert, so definiert man hier entsprechend die Option inet_protocols = ipv4.
  • smtpd_banner
    Definition des Begrüßungstextes, den der Mailserver nach dem Aufbau eingehender Verbindungenvon externen Mailservern ausgibt. Hier wird man i.d.R. aus Sicherheitsgründen lediglich den Hostnamen und den Namen des Mailservers preis geben, nicht aber Versionsangaben oder weiteres.

Neben den beiden vorgenannten Hauptkonfigurationsdateien main.cf und master.cf finden wir im Konfigurationsverzeichnis /etc/postfix noch ein paar Lockup-Tabellen, die bei der RPM-Installation automatisch angelegt wurden.

 # ls -l --hide=*.cf --hide=header_checks /etc/postfix/
total 112
-rw-r--r--. 1 root root 21006 Sep 24 19:22 access
-rw-r--r--. 1 root root 11683 Sep 24 19:22 canonical
-rw-r--r--. 1 root root  9904 Sep 24 19:22 generic
-rw-r--r--. 1 root root  6816 Sep 24 19:22 relocated
-rw-r--r--. 1 root root 12549 Sep 24 19:22 transport
-rw-r--r--. 1 root root 12510 Sep 24 19:22 virtual

Den Umgang mit diesen access- und lookup-Tabellen ist im Kapitel Konfiguration unseres MTAs Postfix 2.11 unter CentOS7 detailliert beschrieben.

Möchte man Informationen im Mailheader zum Bewerten verwenden, um so z.B. eine Nachricht zu blocken, kann man dies mit Hilfe der Konfigurationsdatei header_checks realisieren.

 # less /etc/postfix/header_checks
/etc/postfix/header_checks
# HEADER_CHECKS(5)                                              HEADER_CHECKS(5)
#                                                                         
# NAME                                                                    
#        header_checks - Postfix built-in content inspection              
#                                                                           
# SYNOPSIS                                                                     
#        header_checks = pcre:/etc/postfix/header_checks                              
#        mime_header_checks = pcre:/etc/postfix/mime_header_checks                      
#        nested_header_checks = pcre:/etc/postfix/nested_header_checks                   
#        body_checks = pcre:/etc/postfix/body_checks                                         
# 
#        milter_header_checks = pcre:/etc/postfix/milter_header_checks
# 
#        smtp_header_checks = pcre:/etc/postfix/smtp_header_checks
#        smtp_mime_header_checks = pcre:/etc/postfix/smtp_mime_header_checks
#        smtp_nested_header_checks = pcre:/etc/postfix/smtp_nested_header_checks
#        smtp_body_checks = pcre:/etc/postfix/smtp_body_checks
# 
#        postmap -q "string" pcre:/etc/postfix/filename
#        postmap -q - pcre:/etc/postfix/filename <inputfile
# 
# DESCRIPTION
#        This  document  describes access control on the content of
#        message headers and message body lines; it is  implemented
#        by  the  Postfix  cleanup(8) server before mail is queued.
#        See access(5) for access control  on  remote  SMTP  client
#        information.
# 
#        Each  message  header  or  message  body  line is compared
#        against a list of patterns.  When a  match  is  found  the
#        corresponding action is executed, and the matching process
#        is repeated for the next message header  or  message  body
#        line.
# 
#        Note: message headers are examined one logical header at a
#        time, even when a message  header  spans  multiple  lines.
#        Body lines are always examined one line at a time.
# 
#        For  examples, see the EXAMPLES section at the end of this
#        manual page.
# 
#        Postfix header or body_checks are designed to stop a flood
#        of  mail from worms or viruses; they do not decode attach-
#        ments, and they do not unzip archives. See  the  documents
#        referenced  below  in the README FILES section if you need
#        more sophisticated content analysis.
# 
# FILTERS WHILE RECEIVING MAIL
#        Postfix implements the  following  four  built-in  content
#        inspection classes while receiving mail:
# 
#        header_checks (default: empty)
#               These   are  applied  to  initial  message  headers
#               (except for the headers  that  are  processed  with
#               mime_header_checks).
# 
#        mime_header_checks (default: $header_checks)
#               These  are  applied to MIME related message headers
#               only.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#        nested_header_checks (default: $header_checks)
#               These  are  applied  to message headers of attached
#               email messages (except for  the  headers  that  are
#               processed with mime_header_checks).
# 
#               This feature is available in Postfix 2.0 and later.
# 
#        body_checks
#               These are applied to all other  content,  including
#               multi-part message boundaries.
# 
#               With Postfix versions before 2.0, all content after
#               the initial message headers is treated as body con-
#               tent.
# 
# FILTERS AFTER RECEIVING MAIL
#        Postfix  supports a subset of the built-in content inspec-
#        tion classes after the message is received:
# 
#        milter_header_checks (default: empty)
#               These are applied to headers that  are  added  with
#               Milter applications.
# 
#               This feature is available in Postfix 2.7 and later.
# 
# FILTERS WHILE DELIVERING MAIL
#        Postfix supports all four content inspection classes while
#        delivering mail via SMTP.
# 
#        smtp_header_checks (default: empty)
# 
#        smtp_mime_header_checks (default: empty)
# 
#        smtp_nested_header_checks (default: empty)
# 
#        smtp_body_checks (default: empty)
#               These  features  are  available  in Postfix 2.5 and
#               later.
# 
# COMPATIBILITY
#        With Postfix version 2.2 and earlier specify "postmap -fq"
#        to query a table that contains case sensitive patterns. By
#        default, regexp: and pcre: patterns are case  insensitive.
# 
# TABLE FORMAT
#        This  document  assumes  that header and body_checks rules
#        are specified in the form of  Postfix  regular  expression
#        lookup  tables.  Usually  the best performance is obtained
#        with pcre (Perl Compatible Regular Expression) tables. The
#        regexp  (POSIX  regular  expressions)  tables  are usually
#        slower, but more widely available.  Use the command "post-
#        conf  -m" to find out what lookup table types your Postfix
#        system supports.
# 
#        The general format of Postfix regular expression tables is
#        given  below.   For  a  discussion  of specific pattern or
#        flags  syntax,  see  pcre_table(5)   or   regexp_table(5),
#        respectively.
# 
#        /pattern/flags action
#               When  /pattern/  matches  the input string, execute
#               the corresponding action. See below for a  list  of
#               possible actions.
# 
#        !/pattern/flags action
#               When  /pattern/  does  not  match the input string,
#               execute the corresponding action.
# 
#        if /pattern/flags
# 
#        endif  Match the input string against the patterns between
#               if  and endif, if and only if the same input string
#               also matches /pattern/. The if..endif can nest.
# 
#               Note: do not prepend whitespace to patterns  inside
#               if..endif.
# 
#        if !/pattern/flags
# 
#        endif  Match the input string against the patterns between
#               if and endif, if and only if the same input  string
#               does not match /pattern/. The if..endif can nest.
# 
#        blank lines and comments
#               Empty  lines and whitespace-only lines are ignored,
#               as are lines whose first  non-whitespace  character
#               is a `#'.
# 
#        multi-line text
#               A  pattern/action  line  starts with non-whitespace
#               text. A line that starts with whitespace  continues
#               a logical line.
# 
# TABLE SEARCH ORDER
#        For  each  line of message input, the patterns are applied
#        in the order as specified in the table. When a pattern  is
#        found  that  matches  the  input  line,  the corresponding
#        action is  executed  and  then  the  next  input  line  is
#        inspected.
# 
# TEXT SUBSTITUTION
#        Substitution  of  substrings  from  the matched expression
#        into the action string is possible using the  conventional
#        Perl  syntax  ($1,  $2,  etc.).   The macros in the result
#        string may need to be written as  ${n}  or  $(n)  if  they
#        aren't followed by whitespace.
# 
#        Note:  since negated patterns (those preceded by !) return
#        a result when the expression does not match, substitutions
#        are not available for negated patterns.
# 
# ACTIONS
#        Action names are case insensitive. They are shown in upper
#        case for consistency with other Postfix documentation.
# 
#        DISCARD optional text...
#               Claim successful delivery and silently discard  the
#               message.   Log the optional text if specified, oth-
#               erwise log a generic message.
# 
#               Note:  this  action  disables  further  header   or
#               body_checks  inspection  of the current message and
#               affects all recipients.  To discard only one recip-
#               ient without discarding the entire message, use the
#               transport(5) table to direct mail to the discard(8)
#               service.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#               This feature is not supported with smtp header/body
#               checks.
# 
#        DUNNO  Pretend  that the input line did not match any pat-
#               tern, and inspect the next input line. This  action
#               can be used to shorten the table search.
# 
#               For  backwards  compatibility reasons, Postfix also
#               accepts OK but it is (and always has been)  treated
#               as DUNNO.
# 
#               This feature is available in Postfix 2.1 and later.
# 
#        FILTER transport:destination
#               After the message is queued, send the  entire  mes-
#               sage through the specified external content filter.
#               The transport name specifies the first field  of  a
#               mail  delivery  agent  definition in master.cf; the
#               syntax of the next-hop destination is described  in
#               the  manual  page  of  the  corresponding  delivery
#               agent.  More  information  about  external  content
#               filters is in the Postfix FILTER_README file.
# 
#               Note  1: do not use $number regular expression sub-
#               stitutions for transport or destination unless  you
#               know that the information has a trusted origin.
# 
#               Note  2:  this  action  overrides  the main.cf con-
#               tent_filter setting, and affects all recipients  of
#               the  message.  In  the  case  that  multiple FILTER
#               actions fire, only the last one is executed.
# 
#               Note 3: the purpose of the  FILTER  command  is  to
#               override  message routing.  To override the recipi-
#               ent's transport but not the  next-hop  destination,
#               specify  an  empty  filter destination (Postfix 2.7
#               and later), or specify a transport:destination that
#               delivers   through  a  different  Postfix  instance
#               (Postfix 2.6 and earlier). Other options are  using
#               the  recipient-dependent transport_maps or the sen-
#               der-dependent   sender_dependent_default_transport-
#               _maps features.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#               This feature is not supported with smtp header/body
#               checks.
# 
#        HOLD optional text...
#               Arrange  for  the  message to be placed on the hold
#               queue, and inspect the next input line.   The  mes-
#               sage  remains  on hold until someone either deletes
#               it or releases it for delivery.  Log  the  optional
#               text if specified, otherwise log a generic message.
# 
#               Mail that is placed on hold can  be  examined  with
#               the  postcat(1)  command,  and  can be destroyed or
#               released with the postsuper(1) command.
# 
#               Note: use "postsuper -r" to release mail  that  was
#               kept  on  hold for a significant fraction of $maxi-
#               mal_queue_lifetime  or  $bounce_queue_lifetime,  or
#               longer.  Use "postsuper -H" only for mail that will
#               not expire within a few delivery attempts.
# 
#               Note: this action affects  all  recipients  of  the
#               message.
# 
#               This feature is available in Postfix 2.0 and later.
# 
#               This feature is not supported with smtp header/body
#               checks.
# 
#        IGNORE Delete the current line from the input, and inspect
#               the next input line.
# 
#        INFO optional text...
#               Log an "info:" record with the optional text... (or
#               log  a  generic  text),  and inspect the next input
#               line. This action is useful for routine logging  or
#               for debugging.
# 
#               This feature is available in Postfix 2.8 and later.
# 
#        PREPEND text...
#               Prepend one  line  with  the  specified  text,  and
#               inspect the next input line.
# 
#               Notes:
# 
#               o      The  prepended  text is output on a separate
#                      line,  immediately  before  the  input  that
#                      triggered the PREPEND action.
# 
#               o      The prepended text is not considered part of
#                      the input  stream:  it  is  not  subject  to
#                      header/body checks or address rewriting, and
#                      it does not affect the way that Postfix adds
#                      missing message headers.
# 
#               o      When prepending text before a message header
#                      line, the prepended text must begin  with  a
#                      valid message header label.
# 
#               o      This action cannot be used to prepend multi-
#                      line text.
# 
#               This feature is available in Postfix 2.1 and later.
# 
#               This   feature   is   not   supported   with   mil-
#               ter_header_checks.
# 
#        REDIRECT user@domain
#               Write a message redirection request  to  the  queue
#               file,  and  inspect  the next input line. After the
#               message is queued, it will be sent to the specified
#               address instead of the intended recipient(s).
# 
#               Note:  this action overrides the FILTER action, and
#               affects all recipients of the message. If  multiple
#               REDIRECT  actions  fire,  only the last one is exe-
#               cuted.
# 
#               This feature is available in Postfix 2.1 and later.
# 
#               This feature is not supported with smtp header/body
#               checks.
# 
#        REPLACE text...
#               Replace the current line with the  specified  text,
#               and inspect the next input line.
# 
#               This feature is available in Postfix 2.2 and later.
#               The description below applies to Postfix 2.2.2  and
#               later.
# 
#               Notes:
# 
#               o      When  replacing  a  message header line, the
#                      replacement text must  begin  with  a  valid
#                      header label.
# 
#               o      The  replaced text remains part of the input
#                      stream. Unlike the result from  the  PREPEND
#                      action,  a  replaced  message  header may be
#                      subject to address rewriting and may  affect
#                      the  way  that  Postfix adds missing message
#                      headers.
# 
#        REJECT optional text...
#               Reject the  entire  message.  Reply  with  optional
#               text... when the optional text is specified, other-
#               wise reply with a generic error message.
# 
#               Note:  this  action  disables  further  header   or
#               body_checks  inspection  of the current message and
#               affects all recipients.
# 
#               Postfix version 2.3 and later support enhanced sta-
#               tus codes.  When no code is specified at the begin-
#               ning of optional text..., Postfix inserts a default
#               enhanced status code of "5.7.1".
# 
#               This feature is not supported with smtp header/body
#               checks.
# 
#        WARN optional text...
#               Log a "warning:" record with the  optional  text...
#               (or log a generic text), and inspect the next input
#               line. This action is useful for debugging  and  for
#               testing  a  pattern  before  applying  more drastic
#               actions.
# 
# BUGS
#        Empty lines never match, because some map types mis-behave
#        when  given  a zero-length search string.  This limitation
#        may be removed for regular expression tables in  a  future
#        release.
# 
#        Many  people  overlook  the main limitations of header and
#        body_checks rules.
# 
#        o      These rules operate on one logical  message  header
#               or one body line at a time. A decision made for one
#               line is not carried over to the next line.
# 
#        o      If text in the message body is encoded  (RFC  2045)
#               then the rules need to be specified for the encoded
#               form.
# 
#        o      Likewise, when message  headers  are  encoded  (RFC
#               2047)  then  the rules need to be specified for the
#               encoded form.
# 
#        Message headers added by the cleanup(8) daemon itself  are
#        excluded from inspection. Examples of such message headers
#        are From:, To:, Message-ID:, Date:.
# 
#        Message headers deleted by the cleanup(8) daemon  will  be
#        examined before they are deleted. Examples are: Bcc:, Con-
#        tent-Length:, Return-Path:.
# 
# CONFIGURATION PARAMETERS
#        body_checks
#               Lookup tables with content filter rules for message
#               body lines.  These filters see one physical line at
#               a time, in chunks  of  at  most  $line_length_limit
#               bytes.
# 
#        body_checks_size_limit
#               The  amount  of  content  per  message body segment
#               (attachment) that is subjected to $body_checks fil-
#               tering.
# 
#        header_checks
# 
#        mime_header_checks (default: $header_checks)
# 
#        nested_header_checks (default: $header_checks)
#               Lookup tables with content filter rules for message
#               header lines: respectively, these  are  applied  to
#               the  initial  message  headers  (not including MIME
#               headers), to the MIME headers anywhere in the  mes-
#               sage,  and  to the initial headers of attached mes-
#               sages.
# 
#               Note: these filters see one logical message  header
#               at  a time, even when a message header spans multi-
#               ple lines. Message headers  that  are  longer  than
#               $header_size_limit characters are truncated.
# 
#        disable_mime_input_processing
#               While  receiving mail, give no special treatment to
#               MIME related message headers; all  text  after  the
#               initial message headers is considered to be part of
#               the message body. This means that header_checks  is
#               applied  to  all  the  initial message headers, and
#               that body_checks is applied to the remainder of the
#               message.
# 
#               Note:  when  used  in this manner, body_checks will
#               process a multi-line message header one line  at  a
#               time.
# 
# EXAMPLES
#        Header  pattern  to  block  attachments with bad file name
#        extensions.  For convenience, the PCRE /x flag  is  speci-
#        fied,  so  that  there  is no need to collapse the pattern
#        into  a  single  line  of  text.   The  purpose   of   the
#        [[:xdigit:]] sub-expressions is to recognize Windows CLSID
#        strings.
# 
#        /etc/postfix/main.cf:
#            header_checks = pcre:/etc/postfix/header_checks.pcre
# 
#        /etc/postfix/header_checks.pcre:
#            /^Content-(Disposition|Type).*name\s*=\s*"?(.*(\.|=2E)(
#              ade|adp|asp|bas|bat|chm|cmd|com|cpl|crt|dll|exe|
#              hlp|ht[at]|
#              inf|ins|isp|jse?|lnk|md[betw]|ms[cipt]|nws|
#              \{[[:xdigit:]]{8}(?:-[[:xdigit:]]{4}){3}-[[:xdigit:]]{12}\}|
#              ops|pcd|pif|prf|reg|sc[frt]|sh[bsm]|swf|
#              vb[esx]?|vxd|ws[cfh]))(\?=)?"?\s*(;|$)/x
#                REJECT Attachment name "$2" may not end with ".$4"
# 
#        Body pattern to stop a specific HTML browser vulnerability
#        exploit.
# 
#        /etc/postfix/main.cf:
#            body_checks = regexp:/etc/postfix/body_checks
# 
#        /etc/postfix/body_checks:
#            /^<iframe src=(3D)?cid:.* height=(3D)?0 width=(3D)?0>$/
#                REJECT IFRAME vulnerability exploit
# 
# SEE ALSO
#        cleanup(8), canonicalize and enqueue Postfix message
#        pcre_table(5), format of PCRE lookup tables
#        regexp_table(5), format of POSIX regular expression tables
#        postconf(1), Postfix configuration utility
#        postmap(1), Postfix lookup table management
#        postsuper(1), Postfix janitor
#        postcat(1), show Postfix queue file contents
#        RFC 2045, base64 and quoted-printable encoding rules
#        RFC 2047, message header encoding for non-ASCII text
# 
# README FILES
#        Use  "postconf  readme_directory" or "postconf html_direc-
#        tory" to locate this information.
#        DATABASE_README, Postfix lookup table overview
#        CONTENT_INSPECTION_README, Postfix content inspection overview
#        BUILTIN_FILTER_README, Postfix built-in content inspection
#        BACKSCATTER_README, blocking returned forged mail
# 
# LICENSE
#        The Secure Mailer license must be  distributed  with  this
#        software.
# 
# AUTHOR(S)
#        Wietse Venema
#        IBM T.J. Watson Research
#        P.O. Box 704
#        Yorktown Heights, NY 10598, USA
# 
#

Wie dies im Detail von Statten geht werden wir uns in einem separaten Schritt Grundabsicherung von Postfix noch genauer ansehen. FIXME

Damit fremde MTAs4) auf SMTP-Port 25 und unsere Kunden mit deren MUAs5) auf dem Submission-Port 587 ihre Nachrichten bei unserem Postfix-Mailserver einliefern können, müssen wir für diese noch Änderungen am Paketfilter firewalld vornehmen.

 # firewall-cmd --permanent --zone=public --add-port=25/tcp
 success
 # firewall-cmd --permanent --zone=public --add-port=587/tcp
 success

Anschließend können wir den Firewall-Daemon einmal durchstarten und anschließend überprüfen, ob die Regeln auch entsprechend unserer Definition, gezogen haben.

 # firewall-cmd --reload
 success

Abschließend prüfen wir noch, ob die Erweiterung unseres Paketfilter aktiv ist.

 # iptables -nvL IN_public_allow
Chain IN_public_allow (1 references)
 pkts bytes target     prot opt in     out     source               destination         
    0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp dpt:22 ctstate NEW
    0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp dpt:25 ctstate NEW
    0     0 ACCEPT     tcp  --  *      *       0.0.0.0/0            0.0.0.0/0            tcp dpt:587 ctstate NEW
 # systemctl start postfix.service

Im Maillog wird der Start unseres Postfix-Servers entsprechend vermerkt.

 # less /var/log/maillog
Oct 10 22:41:25 vml000087.dmz.nausch.org systemd[1]: Starting Postfix Mail Transport Agent...
Oct 10 22:41:26 vml000087.dmz.nausch.org postfix/master[30590]: daemon started -- version 2.11.1, configuration /etc/postfix
Oct 10 22:41:26 vml000087.dmz.nausch.org systemd[1]: Started Postfix Mail Transport Agent.
 # systemctl status postfix.service
postfix.service - Postfix Mail Transport Agent
   Loaded: loaded (/usr/lib/systemd/system/postfix.service; enabled)
   Active: active (running) since Fri 2014-10-10 22:41:26 CEST; 1min 11s ago
  Process: 30501 ExecStop=/usr/sbin/postfix stop (code=exited, status=0/SUCCESS)
  Process: 30517 ExecStart=/usr/sbin/postfix start (code=exited, status=0/SUCCESS)
  Process: 30515 ExecStartPre=/usr/libexec/postfix/chroot-update (code=exited, status=0/SUCCESS)
  Process: 30513 ExecStartPre=/usr/libexec/postfix/aliasesdb (code=exited, status=0/SUCCESS)
 Main PID: 30590 (master)
   CGroup: /system.slice/postfix.service
           ├─30590 /usr/libexec/postfix/master -w
           ├─30591 pickup -l -t unix -u
           └─30592 qmgr -l -t unix -u

Oct 10 22:41:25 vml000087.dmz.nausch.org systemd[1]: Starting Postfix Mail Transport Agent...
Oct 10 22:41:26 vml000087.dmz.nausch.org postfix/master[30590]: daemon started -- version 2.11.1, configuration /etc/postfix
Oct 10 22:41:26 vml000087.dmz.nausch.org systemd[1]: Started Postfix Mail Transport Agent.

Wollen wir den Daemon beim Hochfahren des Systems automatisch starten, greifen wir auf den Befehl systemctl zurück.

 # systemctl enable postfix.service

Möchten wir uns vergewissern, ob der Daemon beim Systemstart gestartet wird oder nicht, erfahren wir ebenfalls mit dem Befehl systemctl.

 # systemctl is-enabled postfix.service
 enabled

Startet der Server nicht automatisch, wird uns ein „disabled“ zurückgemeldet.

Mit der minimalen Konfiguration unseres Postfix haben wir bereits einen lauffähigen MTA. Zum Testen verwenden wir das programm telnet. Die Eingaben am testenden Client sind in der Farbe blau und die Rückmeldungen unseres Dovecot-Servers in der Farbe hellgrau gekennzeichnet. Die Ausgaben des Befehls telnet sind in der Farbe schwarz eingefärbt.

$ telnet ::1 25
Trying ::1...
Connected to ::1.
Escape character is '^]'.
220 vml000087.dmz.nausch.org ESMTP Postfix
helo foo
250 vml000087.dmz.nausch.org
mail from:<>
250 2.1.0 OK
rcpt to:<django@vml000087.dmz.nausch.org>>
250 2.1.0 OK
DATA
354 End data with <CR><LF>.<CR><LF>
From: michael@nausch.org
To: django@vml000087.dmz.nausch.org
Subject: erste testmail
Date: heute

test
.
250 2.0.0 Ok: queued as 5F251C00088
quit
221 2.0.0 Bye
Connection closed by foreign host.

Die Message-ID 5F251C00088 finden wir dann auch im Maillog wieder.

 # tail -n7 /var/log/maillog 
 Oct 13 22:15:55 vml000087 postfix/smtpd[4304]: connect from localhost[::1]
 Oct 13 22:16:34 vml000087 postfix/smtpd[4304]: 5F251C00088: client=localhost[::1]
 Oct 13 22:17:13 vml000087 postfix/cleanup[4308]: 5F251C00088: message-id=<20141013201634.5F251C00088@vml000087.dmz.nausch.org>
 Oct 13 22:17:13 vml000087 postfix/qmgr[2202]: 5F251C00088: from=<>, size=364, nrcpt=1 (queue active)
 Oct 13 22:17:13 vml000087 postfix/local[4309]: 5F251C00088: to=<django@vml000087.dmz.nausch.org>, relay=local, delay=63, delays=63/0.02/0/0.02, dsn=2.0.0, status=sent (delivered to mailbox)
 Oct 13 22:17:13 vml000087 postfix/qmgr[2202]: 5F251C00088: removed
 Oct 13 22:17:16 vml000087 postfix/smtpd[4304]: disconnect from localhost[::1]

Auf unserem Festplatten wurde die eMail auch entsprechend abgespeichert.

/var/spool/mail/
├── django
└── root
 # cat /var/spool/mail/django
From MAILER-DAEMON  Mon Oct 13 22:17:13 2014
Return-Path: <>
X-Original-To: django@vml000087.dmz.nausch.org
Delivered-To: django@vml000087.dmz.nausch.org
Received: from foo (localhost [IPv6:::1])
        by vml000087.dmz.nausch.org (Postfix) with SMTP id 5F251C00088
        for <django@vml000087.dmz.nausch.org>; Mon, 13 Oct 2014 22:16:10 +0200 (CEST)
From: michael@nausch.org
To: django@vml000087.dmz.nausch.org
Subject: erste testmail
Date: heute
Message-Id: <20141013201634.5F251C00088@vml000087.dmz.nausch.org>

test

Links


1) , 4)
Mail Transfer Agent
2)
DNS-based Authentication of Named Entities
3)
Domain Name System Security Extensions
5)
Mail User Agent
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