[Kamailio-Users] Having problems using RTPProxy to bridge internal/external networks

Örn Arnarson orn at arnarson.net
Wed Oct 14 17:56:52 CEST 2009


I'm having a similar problem at the moment;

In my setup, I have two physical interfaces, one private and one
public. As with you, I have managed to get SIP flowing without
problems with the correct IP headers re-written.

With the RTP, I've been struggling. I've been where you are at now,
but currently, through fix_nated_sdp and rtpproxy_offer I've managed
to get the correct IP addresses in the SDP header; thus I have
incoming RTP from both sides to the correct respective IP addresses of
kamailio. That is, the private one sends to the private IP address,
and the public one sends to the public IP address.
Kamailio, however, doesn't do anything with these packages. It gives
no reply about ICMP port unreachable, nor does it forward it. So,
packets are streaming in to kamailio/rtpproxy from both ends, but
nothing is coming out on either end.

I have RTP proxy running in bridged mode, with the flag -l
ext.ip.address/int.ip.address.

As with Joe, I'd appreciate any pointers.

Best regards,
Örn

On Tue, Oct 13, 2009 at 10:12 PM, Joe Hart <jhart at evaristesys.com> wrote:
> Hi all,
>
> For a project on which I'm currently working, I am having some problems
> figuring out how to correctly configure Kamailio to communicate with RTP
> Proxy in order to send media into and out of a network with private IP
> address ranges.
>
> I have a proxy set up to send the SIP traffic, and all of this is working
> fine.  However, I'm having some trouble getting the RTP Proxy set up.
>  Currently, when the call is connected, the offer/answer is made and RTP
> Proxy seems to be taking over, but I'm having trouble getting my audio to
> flow in both directions.
>
> Examination of the traffic coming into and out of this machine seems to
> indicate that the IP addresses aren't being mangled correctly. Specifically,
> it appears the internal IP address isn't being changed to reflect the IP
> address of the machine on which RTP Proxy is running, so that when the
> caller tries to send audio back, the IP it's given to reply to is 10.10.x.x,
> which obviously won't work.
>
> I have tried experimenting with specifically setting IP addresses in the
> rtpproxy_offer() and _answer() methods to no avail, as well as setting
> various flags in those methods.  However, I must admit that I'm not entirely
> sure what's happening under the hood with these methods, or what rtpproxy is
> doing with that information when it gets it.  Rather than continue to hack
> at this by trial and error, I'm hoping someone here can point me in the
> right direction.
>
> Any advice, example code or pep talks would be greatly appreciated.
>
> Thanks in advance,
>
> --
> Joe Hart
> Voice Systems Integrator
> Evariste Systems
> Web     : http://www.evaristesys.com/
> Tel     : (+1) (678) 954-0670
> Direct  : (+1) (678) 954-0673
>
> _______________________________________________
> Kamailio (OpenSER) - Users mailing list
> Users at lists.kamailio.org
> http://lists.kamailio.org/cgi-bin/mailman/listinfo/users
> http://lists.openser-project.org/cgi-bin/mailman/listinfo/users
>



More information about the Users mailing list