An earlier post discussed issues I had calling between Sipura and x-lite. After receiving a lot of help that issue was resolved ... sort of. For those interested, calls between two x-lite UAs through an incorrectly configured mediaproxy had two-way audio but calls between x-lite and sipura did not. I now get one-way audio between the Sipura and x-lite when the call goes over the internet and back into the same NAT, but get no audio when the calls goes out and back into another NAT. I am using: ser 0.9.1 mediaproxy 1.3.0 ser.cfg from onsip.org I have posted the relevant Invites from 4 scenarios below and would appreciate any insight: 1. Sipura to x-Lite on same NAT (one-way audio) 2. Sipura to x-Lite on different NAT (no audio) 3. x-Lite to x-Lite on same NAT (audio OK) 4. x-Lite to x-Lite on different NAT (audio OK) The problem may be that the c record is the local IP address for the Sipura with the Sipura calls whereas with the x-lite calls it is the public IP address. I've checked the settings on the sipura and the NAT settings = no (I think this means leave NAT to mediaproxy) whilst the Via settings = yes. *Scenario 1* The following invite is on a call from Sipura (beattiek) to x-Lite (beattiec) on the same NAT. Audio is heard in one direction (from x-lite to Sipura). Sipura -> Nat 1 -> Proxy -> Nat 1 -> x-lite U 147.202.44.XXX:5060 -> 60.234.199.XXX:1028 INVITE sip:beattiea@60.234.199.XXX:5060 SIP/2.0..Record-Route: <sip:alias1@147.202.44.XXX:5060;nat=yes;ftag=1df09ec95856c84do0;lr=on> ..Via: SIP/2.0/UDP 147.202.44.XXX;branch=z9hG4bK6799.73035531.0..Via: SIP/2.0/UDP 192.168.0.11:5060;received=60.234.199.XXX;branch=z9hG4b K-d4727cc1;rport=5060..From: Cameron's sipura 2000 <sip:beattiek@beta.mydomain.co.nz>;tag=1df09ec95856c84do0..To: <sip:alias1@beta. mydomain.co.nz>..Call-ID: 91508d79-f1c0295d@192.168.0.11..CSeq: 102 INVITE..Max-Forwards: 16..Contact: Cameron's sipura 2000 <sip:beatt iek@60.234.199.XXX:5060>..Expires: 240..User-Agent: Sipura/SPA2000-2.0.13(g)..Content-Length: 424..Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER..Supported: x-sipura..Content-Type: application/sdp....v=0..o=- 8343043 8343043 IN IP4 192.168.0.11..s=-..c=IN IP 4 192.168.0.11..t=0 0..m=audio 16454 RTP/AVP 0 2 4 8 18 96 97 98 100 101..a=rtpmap:0 PCMU/8000..a=rtpmap:2 G726-32/8000..a=rtpmap:4 G723/ 8000..a=rtpmap:8 PCMA/8000..a=rtpmap:18 G729a/8000..a=rtpmap:96 G726-40/8000..a=rtpmap:97 G726-24/8000..a=rtpmap:98 G726-16/8000..a=rtpma p:100 NSE/8000..a=rtpmap:101 telephone-event/8000..a=fmtp:101 0-15..a=ptime:30..a=sendrecv.. *Scenario 2* The following invite is on a call from Sipura (beattiek) to x-Lite (pearcej) on a separate NAT. No audio is heard in either direction. Sipura -> Nat 1 -> Proxy -> Nat 2 -> x-lite U 147.202.44.XXX:5060 -> 219.88.100.XX:5060 INVITE sip:pearcej@219.88.100.XX:5060 SIP/2.0..Record-Route: <sip:alias2@147.202.44.XXX:5060;nat=yes;ftag=3c35fa19eb73610fo0;lr=on>..Via : SIP/2.0/UDP 147.202.44.XXX;branch=z9hG4bK810a.ea51b996.0..Via: SIP/2.0/UDP 192.168.0.11:5060;received=60.234.199.XXX;branch=z9hG4bK-ca5 e9437;rport=5060..From: Cameron's sipura 2000 <sip:beattiek@beta.mydomain.co.nz>;tag=3c35fa19eb73610fo0..To: <sip:alias2@beta.mydomain .co.nz>..Call-ID: 92d1ee61-22aab967@192.168.0.11..CSeq: 102 INVITE..Max-Forwards: 16..Contact: Cameron's sipura 2000 <sip:beattiek@60.2 34.199.XXX:5060>..Expires: 240..User-Agent: Sipura/SPA2000-2.0.13(g)..Content-Length: 424..Allow: ACK, BYE, CANCEL, INFO, INVITE, NOTIFY, OPTIONS, REFER..Supported: x-sipura..Content-Type: application/sdp....v=0..o=- 7997909 7997909 IN IP4 192.168.0.11..s=-..c=IN IP4 192.16 8.0.11..t=0 0..m=audio 16442 RTP/AVP 0 2 4 8 18 96 97 98 100 101..a=rtpmap:0 PCMU/8000..a=rtpmap:2 G726-32/8000..a=rtpmap:4 G723/8000..a= rtpmap:8 PCMA/8000..a=rtpmap:18 G729a/8000..a=rtpmap:96 G726-40/8000..a=rtpmap:97 G726-24/8000..a=rtpmap:98 G726-16/8000..a=rtpmap:100 NS E/8000..a=rtpmap:101 telephone-event/8000..a=fmtp:101 0-15..a=ptime:30..a=sendrecv.. *Scenario 3* The following invite is on a call from x-Lite (beattiec) to x-Lite (beattiea) on the same NAT. x-lite-> Nat 1 -> Proxy -> Nat 1 -> x-lite U 147.202.44.XXX:5060 -> 60.234.199.XXX:1028 INVITE sip:beattiea@60.234.199.XXX:5060 SIP/2.0..Record-Route: <sip:beattiea@147.202.44.XXX:5060;nat=yes;ftag=251677925;lr=on>..Via: SIP/ 2.0/UDP 147.202.44.XXX;branch=z9hG4bKd72b.189eef55.0..Via: SIP/2.0/UDP 60.234.199.XXX:5060;rport=1027;branch=z9hG4bK52D2A416DB7849C4BC88D 0A3B2B4B1D1..From: Cameron's laptop <sip:beattiec@beta.mydomain.co.nz>;tag=251677925..To: <sip:beattiea@beta.mydomain.co.nz>..Contact : <sip:beattiec@60.234.199.XXX:1027>..Call-ID: 0E31A4AE-E92F-46D1-8ACB-7CB7E2FF1641@192.168.0.15..CSeq: 18590 INVITE..Max-Forwards: 16..C ontent-Type: application/sdp..User-Agent: X-Lite release 1103m..Content-Length: 303....v=0..o=beattiec 169182050 169182181 IN IP4 60.234. 199.XXX..s=X-Lite..c=IN IP4 60.234.199.XXX..t=0 0..m=audio 8000 RTP/AVP 0 8 3 98 97 101..a=rtpmap:0 pcmu/8000..a=rtpmap:8 pcma/8000..a=rt pmap:3 gsm/8000..a=rtpmap:98 iLBC/8000..a=rtpmap:97 speex/8000..a=rtpmap:101 telephone-event/8000..a=fmtp:101 0-15.. *Scenario 4* The following invite is on a call from x-Lite (beattiec) to x-Lite (pearcej) on a separate NAT. x-lite -> Nat 1 -> Proxy -> Nat 2 -> x-lite U 147.202.44.XXX:5060 -> 219.88.100.XX:5060 INVITE sip:pearcej@219.88.100.XX:5060 SIP/2.0..Record-Route: <sip:alias2@147.202.44.XXX:5060;nat=yes;ftag=3274571863;lr=on>..Via: SIP/2. 0/UDP 147.202.44.XXX;branch=z9hG4bKa447.eadaf8e4.0..Via: SIP/2.0/UDP 60.234.199.XXX:5060;rport=1027;branch=z9hG4bKED04E2DC4F0846A5B616A13 47747365E..From: Cameron's laptop <sip:beattiec@beta.mydomain.co.nz>;tag=3274571863..To: <sip:alias2@beta.mydomain.co.nz>..Contact: <sip:beattiec@60.234.199.XXX:1027>..Call-ID: 60F12C88-B4A4-44D9-A207-FF7F6A97C3C8@192.168.0.15..CSeq: 7003 INVITE..Max-Forwards: 16..Cont ent-Type: application/sdp..User-Agent: X-Lite release 1103m..Content-Length: 303....v=0..o=beattiec 165963913 165964043 IN IP4 60.234.199 .XXX..s=X-Lite..c=IN IP4 60.234.199.XXX..t=0 0..m=audio 8000 RTP/AVP 0 8 3 98 97 101..a=rtpmap:0 pcmu/8000..a=rtpmap:8 pcma/8000..a=rtpma p:3 gsm/8000..a=rtpmap:98 iLBC/8000..a=rtpmap:97 speex/8000..a=rtpmap:101 telephone-event/8000..a=fmtp:101 0-15.. Many thanks for any help received. Regards Cameron Beattie