#########################################################################
##
# SPECIFY YOUR NTP SERVERS

# Most computers using chrony will send measurement requests to one or
# more 'NTP servers'.  You will probably find that your Internet Service
# Provider or company have one or more NTP servers that you can specify.
# Failing that, there are a lot of public NTP servers.  There is a list
# you can access at http://support.ntp.org/bin/view/Servers/WebHome or
# you can use servers from the pool.ntp.org project.

server 0.pool.ntp.org iburst
server 1.pool.ntp.org iburst
server 2.pool.ntp.org iburst

# However, for dial-up use you probably want these instead.  The word
# 'offline' means that the server is not visible at boot time.  Use
# chronyc's 'online' command to tell chronyd that these servers have
# become visible after you go on-line.

# server 0.pool.ntp.org offline
# server 1.pool.ntp.org offline
# server 2.pool.ntp.org offline


#########################################################################
##
# AVOIDING POTENTIALLY BOGUS CHANGES TO YOUR CLOCK

# To avoid changes being made to your computer's gain/loss compensation
# when the measurement history is too erratic, you might want to enable
# one of the following lines.  The first seems good for dial-up (or
# other high-latency connections like slow leased lines), the second
# seems OK for a LAN environment.

# maxupdateskew 100
# maxupdateskew 5


#########################################################################
##
# FILENAMES ETC

# Chrony likes to keep information about your computer's clock in files.
# The 'driftfile' stores the computer's clock gain/loss rate in parts
# per million.  When chronyd starts, the system clock can be tuned
# immediately so that it doesn't gain or lose any more time.  You
# generally want this, so it is uncommented.

driftfile /var/lib/chrony/drift

# If you want to use the program called chronyc to configure aspects of
# chronyd's operation once it is running (e.g. tell it the Internet link
# has gone up or down), you need a password.  This is stored in the
# following keys file.  (You also need keys to support authenticated NTP
# exchanges between cooperating machines.)  Again, this option is
# assumed by default.

keyfile /etc/chrony.keys

# Tell chronyd which numbered key in the file is used as the password
# for chronyc. (You can pick any integer up to 2**32-1.  '1' is just a
# default.  Using another value will _NOT_ increase security.)

commandkey 1

# Generate command key if missing.
generatecommandkey

# chronyd can save the measurement history for the servers to files when
# it it exits.  This is useful in 2 situations:
#
# 1. On Linux, if you stop chronyd and restart it with '-r' (e.g. after
# an upgrade), the old measurements will still be relevant when chronyd
# is restarted.  This will reduce the time needed to get accurate
# gain/loss measurements, especially with a dial-up link.
#
# 2. Again on Linux, if you use the RTC support and start chronyd with
# '-r -s' on bootup, measurements from the last boot will still be
# useful (the real time clock is used to 'flywheel' chronyd between
# boots).
#
# Enable these two options to use this.

# dumponexit
# dumpdir /var/lib/chrony

# chronyd writes its process ID to a file.  If you try to start a second
# copy of chronyd, it will detect that the process named in the file is
# still running and bail out.  If you want to change the path to the PID
# file, uncomment this line and edit it.  The default path is shown.

# pidfile /var/run/chronyd.pid


#########################################################################
##
# INITIAL CLOCK CORRECTION
# This option is useful to quickly correct the clock on start if it's
# off by a large amount.  The value '10' means that if the error is less
# than 10 seconds, it will be gradually removed by speeding up or
# slowing down your computer's clock until it is correct.  If the error
# is above 10 seconds, an immediate time jump will be applied to correct
# it.  The value '1' means the step is allowed only on the first update
# of the clock.  Some software can get upset if the system clock jumps
# (especially backwards), so be careful!

makestep 10 3


#########################################################################
##
# LOGGING

# If you want to log information about the time measurements chronyd has
# gathered, you might want to enable the following lines.  You probably
# only need this if you really enjoy looking at the logs, you want to
# produce some graphs of your system's timekeeping performance, or you
# need help in debugging a problem.

# logdir /var/log/chrony
# log measurements statistics tracking

# If you have real time clock support enabled, you might want this line
# this instead:

# log measurements statistics tracking rtc

# Normally, chronyd will keep track of how many times each client
# machine accesses it.  The information can be accessed by the 'clients'
# command of chronyc.  You can disable this facility by uncommenting the
# following line.  This will save a bit of memory if you have many
# clients.

# noclientlog

# The clientlog size is limited to 512KB by default.  If you have many
# clients, especially in many different subnets, you might want to
# increase the limit.

# clientloglimit 4194304


#########################################################################
##
# REPORTING BIG CLOCK CHANGES

# Perhaps you want to know if chronyd suddenly detects any large error
# in your computer's clock.  This might indicate a fault or a problem
# with the server(s) you are using, for example.
#
# The next option causes a message to be written to syslog when chronyd
# has to correct an error above 0.5 seconds (you can use any amount you
# like).

# logchange 0.5

# The next option will send email to the named person when chronyd has
# to correct an error above 0.5 seconds.  (If you need to send mail to
# several people, you need to set up a mailing list or sendmail alias
# for them and use the address of that.)

# mailonchange wibble@foobar.org 0.5


#########################################################################
##
# COMMAND ACCESS

# The program chronyc is used to show the current operation of chronyd
# and to change parts of its configuration whilst it is running.

# Normally, chronyd will only allow connections from chronyc on the same
# machine as itself.  This is for security.  If you have a subnet
# 192.168.*.* and you want to be able to use chronyc from any machine on
# it, you could uncomment the following line.  (Edit this to your own
# situation.)

# cmdallow 192.168/16

# You can add as many 'cmdallow' and 'cmddeny' lines as you like.  The
# syntax and meaning is the same as for 'allow' and 'deny', except that
# 'cmdallow' and 'cmddeny' control access to the chronyd's command port.

# NOTE, even if the host where you run chronyc is granted access, you
# still need a command key set up and you have to know the password to
# put into chronyc to allow you to modify chronyd's parameters.  By
# default all you can do is view information about chronyd's operation.


#########################################################################
##
# REAL TIME CLOCK

# chronyd can characterise the system's real-time clock.  This is the
# clock that keeps running when the power is turned off, so that the
# machine knows the approximate time when it boots again.  The error at
# a particular epoch and gain/loss rate can be written to a file and
# used later by chronyd when it is started with the '-s' option.
#
# You need to have 'enhanced RTC support' compiled into your Linux
# kernel.  (Note, these options apply only to Linux.)

# rtcfile /var/lib/chrony/rtc

# The 'rtcsync' directive will enable a kernel mode where the system time
# is copied to the real time clock (RTC) every 11 minutes.
# This directive is supported only on Linux and cannot be used when the
# normal RTC tracking is enabled, i.e.  when the 'rtcfile' directive is
# used.
rtcsync

# The 'stratumweight' directive sets how much distance should be added per
# stratum to the synchronisation distance when 'chronyd' selects the
# synchronisation source from available sources. 
# The syntax is: "stratumweight <dist-in-seconds>". By default, it is one
# second.  This usually means that sources with lower stratum will be 
# preferred to sources with higher stratum even when their distance is 
# significantly worse.  Setting 'stratumweight' to 0 makes 'chronyd' 
# ignore stratum when selecting the source.
stratumweight 0


#########################################################################
##
# ACTING AS AN NTP SERVER

# You might want the computer to be an NTP server for other computers.
# e.g.  you might be running chronyd on a dial-up machine that has a LAN
# sitting behind it with several 'satellite' computers on it.

# This option allows the UDP port on which the server understands NTP
# requests to be specified.  For normal servers this option should not
# not be required (the default is 123, the standard NTP port).

# port 123

#
# By default, chronyd does not allow any clients to access it.  You need
# to explicitly enable access using 'allow' and 'deny' directives.
#
# e.g. to enable client access from the 192.168.*.* class B subnet,

# allow 192.168/16

# .. but disallow the 192.168.100.* subnet of that,

# deny 192.168.100/24

# You can have as many allow and deny directives as you need.  The order
# is unimportant.

# If you want chronyd to act as an NTP broadcast server, enable and edit
# (and maybe copy) the following line.  This means that a broadcast
# packet is sent to the address 192.168.1.255 every 60 seconds.  The
# address MUST correspond to the broadcast address of one of the network
# interfaces on your machine.  If you have multiple network interfaces,
# add a broadcast line for each.

# broadcast 60 192.168.1.255

# If you want to present your computer's time for others to synchronise
# with, even if you don't seem to be synchronised to any NTP servers
# yourself, enable the following line.  The value 10 may be varied
# between 1 and 15.  You should avoid small values because you will look
# like a real NTP server.  The value 10 means that you appear to be 10
# NTP 'hops' away from an authoritative source (atomic clock, GPS
# receiver, radio clock etc).

# local stratum 10

# 'chronyd' will trim the rate at which it samples the server during 
# normal operation, the user may wish to constrain the minimum polling 
# interval. This is always defined as a power of 2, so <tt/minpoll 5/ 
# would mean that the polling interval cannot drop below 32 seconds.
# The default is 6 (64 seconds).

minpoll 6

# In a similar way, the user may wish to constrain the maximum polling
# interval.  Again this is specified as a power of 2, so <tt/maxpoll 9/
# indicates that the polling interval must stay at or below 512 seconds.
# The default is 10 (1024 seconds).

maxpoll 10

# Target number of measurements to use for the regression algorithm
# which 'chronyd' will try to maintain by adjusting polling interval
# between 'minpoll' and 'maxpoll'.  A higher target makes 'chronyd'
# prefer shorter polling intervals.  The default is 6 and a useful
# range is 6 to 60.

polltarget 6

# 'chronyd' uses the network round-trip delay to the server to determine
# how accurate a particular measurement is likely to be. Long round-trip 
# delays indicate that the request, or the response, or both were delayed.
# If only one of the messages was delayed the measurement error is likely
#  to be substantial.
# 
# For small variations in round trip delay, 'chronyd' uses a weighting 
# scheme when processing the measurements.  However, beyond a certain 
# level of delay the measurements are likely to be so corrupted as to be
# useless. (This is particularly so on dial-up or other slow links, where 
# a long delay probably indicates a highly asymmetric delay caused by the 
# response waiting behind a lot of packets related to a download of some 
# sort).
#
# If the user knows that round trip delays above a certain level should 
# cause the measurement to be ignored, this level can be defined with 
# the maxdelay command.  For example, <tt/maxdelay 0.3/ would indicate 
# that measurements with a round-trip delay of 0.3 seconds or more should
#  be ignored.

# maxdelay 0.3

# Maxdelayratio is similar to the maxdelay option above. 'chronyd' keeps a 
# record of the minimum round-trip delay amongst the previous measure-
# ments that it has buffered.  If a measurement has a round trip delay
# that is greater than the maxdelayratio times the minimum delay, it 
# will be rejected.

# maxdelayratio 0.5

# If a measurement has ratio of the increase in round-trip delay from
# the minimum delay amongst the previous measurements to the standard
# deviation of the previous measurements that is greater than
# maxdelaydevratio, it will be rejected.  The default is 10.0.

# maxdelaydevratio