[Asterisk-Dev] How IAX workd behind the firewall

Craig Southeren craigs at postincrement.com
Mon Jul 12 00:21:48 MST 2004

On Mon, 12 Jul 2004 17:12:51 +1000
Adam Hart <adam at teragen.com.au> wrote:


> > Actually, with SIP you will need 3 ports.   1 for control (5060) and two for RTP.
> > 
> That's H.323 I believe, SIP just uses one RTP port as stated in SDP payloads

Nope - fully compliant RTP requires both the control and data ports.

Of course, an implementation may chose to be non-compliant and not
implement RTCP, but then another endpoint is free to stop the call if it
it does not respond. Cisco gateways are notorious for doing this.


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