How to configure sip and extensions files into Asterisk

 

In this article, we will learn how to configure basic sip.conf and extensions.conf files. These two files are very important configuration files. The sip.conf file holds sip channel related settings. We can define SIP users also in this file, if we dont use ARA (Asterisk Realtime Architecture). The extensions.conf file holds all extensions related information, extension means any number like 1000,1001 which we can dial by dial pad from our soft phone.

See, here SIP user is defined under certain context, and under that context extensions are defined. If you see below sip.conf file definition you can check 1000/1001 SIP users are defined under mycontext context. And in extensions.conf file you can see two extensions definitions are there under [mycontext]

So, we can see relation of SIP users and it's extensions, if SIP user defined under mycontext then that user can dial those extensions only which are defined under [mycontext]

Follow below steps to make basic configurations and make calling working

cd /etc/asterisk

mv sip.conf sip.conf.orig
mv extensions.conf extensions.conf.orig

nano /etc/asterisk/sip.conf and add below content in it and save

[general]

callcounter=yes ; enable device states for SIP devices

rtcachefriends=yes

udpbindaddr=0.0.0.0:5060

externip=your_public_ip

nat=force_rport,comedia

disallow=all

allow=opus

allow=ulaw

allow=alaw

allow=gsm

;you can add this if you don't have add Realtime SIP users

[1000]

type=friend

context=mycontext

secret=1234

host=dynamic

[1001]

type=friend

context=mycontext

secret=1234

host=dynamic 

nano /etc/asterisk/extensions.conf and add below content in it and save

[mycontext]

exten => 1000,1,Dial(SIP/1000)

exten => 1001,1,Dial(SIP/1001)

Now, goto asterisk cli and apply these commands.

asterisk -rvvvv

reload

Register two SIP users into two different soft phones like zoiper and dial each other, you will receive call and can answer.