... 
 
[ttyIAX0]
context=from-iaxmodems
type=friend
secret=P1r4t3nP4rTe1
port=4570
host=dynamic
defaultip=127.0.0.1
deny=0.0.0.0/0.0.0.0
permit=127.0.0.1/255.255.255.255
disallow=all
allow=ulaw
allow=alaw
jitterbuffer=no
requirecalltoken=no

...