[SR-Users] Configuring Kamailio as an upstream proxy for FreeSwitch and which RTP proxy to choose

Fred Posner fred at palner.com
Mon Feb 24 16:07:23 CET 2014

On Mon Feb 24 10:50:07 CET 2014 Sean Kemball wrote:

 > New to Kamailio and FreeSwitch, loosely familiar with SIP mechanics,
 > and not a complete network idiot... but please be gentle. :)


 > Questions:
 > 1.    Should the proposed topology, with Kamailio + an RTP proxy
 > behind a firewall, relaying to FS on an inside interface, work?
 > (Can't see why not)

Yes, you said that your upstream is on the same private network. So it 
should be pretty straight forward.

 > 2.    Does it need a local RTP proxy on the Kamailio box, particularly
 > if we turn off the ASA SIP inspect stuff?

If you are all on the same private network, I would let FreeSWITCH 
handle the RTP, but you can do this a variety of ways.

 > 3.    Can you recommend which RTP proxy to use? There seem to be at
 > least 3 that work with Kamailio. The box is CentOS 6.5, and it would 
 > be nice to use known-to-work packages rather than compile from source.
 > (But eh, if I haveta).

On your scenario, I'd just use FreeSWITCH for the media proxy. Again, 
many different ways to go here.

 > 4.    Can anyone point me to some docs to explain what ports need to
 > be open between the Kamailio box and my upstream proxy/media server?
 > I can be more liberal between inside and DMZ I guess.

Your upstream provider would generally tell you which rtp ports they 
would want opened.

 > 5.    Is static NAT in this environment going to bite me, or should
 > it be OK?

I've never had an upstream provider communicate with me on private nat.

 > 6.    Is there any better documentation that we should be using to
 > make this easier, or should I just man up and try harder?

Man up. =)
Practive makes perfect.

Fred Posner
The Palner Group, Inc.

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