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

[Örn Arnarson]

Oh, I forgot one thing;

I'm using fix_nated_sdp, as previously mentioned. I have a hunch that
because I'm not using force_rtp_proxy/rtpproxy_offer it's not being
relayed (a hunch, because I don't fully understand how rtpproxy
works). Problem is though, I can't get the IP addresses correct by
using rtpproxy_offer.

Regards,
Örn

2009/10/14 Örn Arnarson <orn at arnarson.net>:
> 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
>>
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>