Asterisk Peers from single IP Address

Asterisk Asterisk SIP
1

HI All,

At the moment we are using Asterisk with few ISP SIP Trunks where we are getting the calls. We need that every ISP SIP Trunk to get into a different context. We are authenticating all ISP as a friend by IP Address.
To be able to scale the current infrastructure - we put the SIP Proxy (Kamailio) in front - and forwarding all SIP messages to the Asterisk Farm. But, the problem now is that all SIP Messages are coming from one single IP (kamailio) - and we cannot any more to distinguish between ISP and send calls to the correct context. I was looking on the internet and I found that this could be possible by changing 'From: ’ header and for every SIP Trunk add userfrom field - but in this case, the callerid(num) variable will not be available in asterisk or will be the wrong one. Is there any other methods to solve this issue?

2

You could add a SIP header in Kamailio which identifies which one it is from and then in the dialplan examine the header and use a Goto to the correct context.

3

Note that friend is pointless, and can cause problems, if you are authenticating on IP address. Use peer.

4

I’m not certain, but I think that chan_sip can discriminate on remote port number and that chan_pjsip can also do so on local port number.

5

If they are all going through Kamailio then it’s the same IP address and port, the only difference can be expressed in the signaling itself.