Asterisk + Forking SIP proxy

Hello all!

I need to find a way to use asterisk and a forking proxy to fork INVITE messages.

Does anybody know a free SIP Proxy that can act as such a proxy? Can Asterisk act as one? Can SER or OpenSER do it??

Thanks in advance,


OpenSER (now Kamailio or OpenSIPs) can act as a SIP proxy.

Asterisk is not a proxy. It is an SIP Back to Back User Agent or just an User Agent - depending how you configure it.

Asterisk can actually FORK invite messages in a sense.

Using the Dial() command with multiple SIP destinations you can achieve forking the asterisk way.


It would be a SIP B2BUA in this scenario, but it would achieve the same result.

Considering this case in which we use “Dial” to implement forking, what would be Asterisk´s behavior??

A SIP proxy should cancel all requests it sent once it receives the first 200 OK, do you now if Asterisk would behave like this???

Yes, I believe that asterisk sends a CANCEL to all but the first one to answer. I would do a SIP trace just to ensure… but I believe that it properly supports this behavior.