Thanks very much, very valuable info indeed. I have a few questions that must have been asked a thousand times but I did not find any clear answer in archive : Or can you point me to relevant doc ? 1) fix_nated_sdp : - I guess you use this fonction if you want a nated ua to talk directly to another ua w/o rtproxy ? - what is exactly the sdp field modified ? c ? o ? - is it relevant if you use force_rtp_proxy ? (my guess is no...) 2) force_rport() - Could not figure out the usefulness of this command... Deprecated by fix_nated_contact ? 3)force_rtp_proxy 'f' flag -I really cannot figure out what it does (or does not!) on a sip packet. I would just blindly use it but I would like to understand nonetheless :-) Also I would need an advice : You often see this portion of code at the beginning of a "main routing logic" config file : record_route(); # loose-route processing if (loose_route()) { t_relay(); break; If I am correct it says "if this packet as already been processed by a sip proxy, route it accordingly". But suppose a sip INVITE packet went through a first Proxy, then it will be routed back instead of being correctly processed with lookup("location") for exemple. Would if ( !(method=="INVITE")) { if (loose_route()) { t_relay(); break; }; be more appropriate in this case ? Thanks for your patience - Christian -----Message d'origine----- De : Marian Dumitru [mailto:marian.dumitru@voice-sistem.ro] Envoyé : jeudi 3 février 2005 21:34 À : Christian de Balorre Cc : serusers(a)lists.iptel.org Objet : Re: [Serusers] rtpproxy mess Hi Christian, To configure rtpproxy to do bridging, just set the listen parameter as "-l addr1/addr2". In your configuration I guess addr1 is the private address and addr2 is the public one. But be careful about using a chain of rtpproxy - you can end having a dead-lock for the media relaying. More information about the force_rtp_proxy flags can be found in modules/nathelper/nathelper.c at the beginning; also take a look at the example modules/nathelper/examples/alg.cfg. Best regards, Marian Christian de Balorre wrote: