[OpenSER-Users] why mediaproxy doesn't works?

Hi all, I'm usign 2 users behind the same Nat and I'm using x-lite 3.0. User A calls user B. I want to use mediaproxy between 2 users and I have configured my openser file in that way. Mediaproxy doesn't works, and I've noticed diferences between the "200 OK" message received by user A and that sent by proxy. user A --- INVITE ----> proxy --- INVITE-----> user B user A <----200 OK ---- proxy < ----- 200 OK --- user B this is the 200 OK message sent by proxy to USER A. This has been already manipulated by proxy (chenge IP and PORT in SDP part) for using mediaproxy : SIP/2.0 200 OK Via: SIP/2.0/UDP 192.168.10.245:14620;received=85.18.14.25;branch=z9hG4bK-d87543-37310b5f2633e814-1--d87543-;rport=18267 Record-Route: <sip:137.204.107.138:5060;lr;nat=yes;ftag=910e1011> Contact: <sip:daniel@85.18.14.25:20881;rinstance=8a9df9cdfc3da728> To: "daniel"<sip:daniel@137.204.107.138>;tag=6e33c440 From: "daniel.grotti"<sip:daniel.grotti@137.204.107.138>;tag=910e1011 Call-ID: Y2M3ZDNjOGExN2Q0YTBlYjViMTg1NDAwOTAxZjliMDY. CSeq: 2 INVITE Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO Content-Type: application/sdp User-Agent: X-Lite release 1011s stamp 41150 Content-Length: *375* v=0 o=- 2 2 IN IP4 192.168.10.224 s=CounterPath X-Lite 3.0 *c=IN IP4 137.204.107.138 IP of media relay* t=0 0 *m=audio 60004 RTP/AVP 107 119 100 106 0 105 98 8 101 # 60004 port of mediarelay* a=fmtp:101 0-15 a=rtpmap:107 BV32/16000 a=rtpmap:119 BV32-FEC/16000 a=rtpmap:100 SPEEX/16000 a=rtpmap:106 SPEEX-FEC/16000 a=rtpmap:105 SPEEX-FEC/8000 a=rtpmap:98 iLBC/8000 a=rtpmap:101 telephone-event/8000 a=sendrecv and this is the message sniffed by client A: SIP/2.0 200 OK Via: SIP/2.0/UDP 192.168.10.245:14620;received=85.18.14.25;branch=z9hG4bK-d87543-37310b5f2633e814-1--d87543-;rport=18267 Record-Route: <sip:137.204.107.138:5060;lr;nat=yes;ftag=910e1011> Contact: <sip:daniel@85.18.14.25:20881;rinstance=8a9df9cdfc3da728> To: "daniel"<sip:daniel@137.204.107.138>;tag=6e33c440 From: "daniel.grotti"<sip:daniel.grotti@137.204.107.138>;tag=910e1011 Call-ID: Y2M3ZDNjOGExN2Q0YTBlYjViMTg1NDAwOTAxZjliMDY. CSeq: 2 INVITE Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO Content-Type: application/sdp User-Agent: X-Lite release 1011s stamp 41150 Content-Length: *374* v=0 o=- 2 2 IN IP4 192.168.10.224 s=CounterPath X-Lite 3.0 *c=IN IP4 192.168.10.224* t=0 0 *m=audio 36124 RTP/AVP 107 119 100 106 0 105 98 8 101* a=fmtp:101 0-15 a=rtpmap:107 BV32/16000 a=rtpmap:119 BV32-FEC/16000 a=rtpmap:100 SPEEX/16000 a=rtpmap:106 SPEEX-FEC/16000 a=rtpmap:105 SPEEX-FEC/8000 a=rtpmap:98 iLBC/8000 a=rtpmap:101 telephone-event/8000 a=sendrecv It's the same message but with c and m parameter changed. So, mediaproxy doesn't work and 2 users are directly connected. any suggestion? regards, daniel