Hello List. I have a problem with CANCEL a call behind a NAT enviroment. When i made a call from an endpoint registered in my SER SIP Server with a public IP the CANCEL procces is like behind. As you can see there is a "200 - Cancelling" message (third message) that goes from SER to Endpoint in the port 5060.

U xx.xx.148.235:5060 -> xx.xx.154.35:5060 CANCEL sip:2408171@sipproxy.mydomain.com SIP/2.0 Via: SIP/2.0/UDP xx.xx.148.235:5060;branch=z9hG4bKeb416aaba486 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 To: sip:2408171@sipproxy.mydomain.com Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 CSeq: 86 CANCEL Date: Sun, 21 Nov 2004 14:57:56 GMT User-Agent: AddPac SIP Gateway Content-Length: 0 Max-Forwards: 70

# U xx.xx.154.35:5060 -> xx.xx.148.231:5060 CANCEL sip:005622408171@xx.xx.148.231:5060 SIP/2.0 Record-Route: sip:2408171@xx.xx.154.35;ftag=eb416aaba4;lr=on Via: SIP/2.0/UDP xx.xx.154.35;branch=z9hG4bKe07.c5730461.0 Via: SIP/2.0/UDP xx.xx.148.235:5060;branch=z9hG4bKeb416aaba486 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 To: sip:2408171@sipproxy.mydomain.com Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 CSeq: 86 CANCEL Date: Sun, 21 Nov 2004 14:57:56 GMT User-Agent: AddPac SIP Gateway Content-Length: 0 Max-Forwards: 69 P-hint: H323-Side

# U xx.xx.154.35:5060 -> xx.xx.148.235:5060 SIP/2.0 200 cancelling Via: SIP/2.0/UDP xx.xx.148.235:5060;branch=z9hG4bKeb416aaba486 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 To: sip:2408171@sipproxy.mydomain.com;tag=8acf748d21b6bc66e44e951325ba3f1c-4ce 1 Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 CSeq: 86 CANCEL Server: Sip EXpress router (0.8.14-3 (i386/linux)) Content-Length: 0 Warning: 392 xx.xx.154.35:5060 "Noisy feedback tells: pid=23760 req_src_ip=xx.xx.148.235 req_src_port=5060 in_uri=sip:2408171@sipproxy.mydomain.com out_uri=sip:005622408171@xx.xx.148.231:5060 via_cnt==1"

# U xx.xx.154.35:5060 -> xx.xx.148.235:5060 SIP/2.0 487 Request cancelled Via: SIP/2.0/UDP xx.xx.148.235:5060;branch=z9hG4bKeb416aaba486 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 To: sip:2408171@sipproxy.mydomain.com;tag=8acf748d21b6bc66e44e951325ba3f1c-4ce 1 Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 CSeq: 86 INVITE Server: Sip EXpress router (0.8.14-3 (i386/linux)) Content-Length: 0 Warning: 392 xx.xx.154.35:5060 "Noisy feedback tells: pid=23760 req_src_ip=xx.xx.148.235 req_src_port=5060 in_uri=sip:2408171@sipproxy.mydomain.com out_uri=sip:005622408171@xx.xx.148.231:5060 via_cnt==1"

# U xx.xx.148.231:5060 -> xx.xx.154.35:5060 SIP/2.0 200 OK Via: SIP/2.0/UDP xx.xx.154.35;branch=z9hG4bKe07.c5730461.0 Via: SIP/2.0/UDP xx.xx.148.235:5060;branch=z9hG4bKeb416aaba486 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 To: sip:2408171@sipproxy.mydomain.com Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 CSeq: 86 CANCEL User-Agent: AddPac SIP Gateway Content-Length: 0 Record-Route: sip:2408171@xx.xx.154.35;ftag=eb416aaba4;lr=on

# U xx.xx.148.231:5060 -> xx.xx.154.35:5060 SIP/2.0 487 Request Terminated Via: SIP/2.0/UDP xx.xx.154.35;branch=z9hG4bKe07.c5730461.0 Via: SIP/2.0/UDP xx.xx.148.235:5060;branch=z9hG4bKeb416aaba486 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 To: sip:2408171@sipproxy.mydomain.com;tag=b9410d20a4 Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 CSeq: 86 INVITE User-Agent: AddPac SIP Gateway Content-Length: 0

# U xx.xx.154.35:5060 -> xx.xx.148.231:5060 ACK sip:005622408171@xx.xx.148.231:5060 SIP/2.0 Via: SIP/2.0/UDP xx.xx.154.35;branch=z9hG4bKe07.c5730461.0 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 To: sip:2408171@sipproxy.mydomain.com;tag=b9410d20a4 CSeq: 86 ACK User-Agent: Sip EXpress router(0.8.14-3 (i386/linux)) Content-Length: 0

# U xx.xx.148.235:5060 -> xx.xx.154.35:5060 ACK sip:2408171@sipproxy.mydomain.com SIP/2.0 Via: SIP/2.0/UDP xx.xx.148.235:5060;branch=z9hG4bKeb416aaba486 From: sip:5555848111@sipproxy.mydomain.com;tag=eb416aaba4 To: sip:2408171@sipproxy.mydomain.com;tag=8acf748d21b6bc66e44e951325ba3f1c-4ce 1 Call-ID: ebaca041-57eb-6aef-80ab-0002a4004086@xx.xx.148.235 CSeq: 86 ACK Content-Length: 0 Max-Forwards: 70

Now when i made the same call and i CANCEL it, the "200-Cancelling" message goes directly to port 5060 and not the rport (64435). Why is that?

U xx.xx.148.244:64435 -> xx.xx.154.35:5060 CANCEL sip:2408196@sipproxy.mydomain.com SIP/2.0 Via: SIP/2.0/UDP 192.168.0.191:5060;branch=z9hG4bK2542303ca430 From: sip:5555848110@sipproxy.mydomain.com;tag=2542303ca4 To: sip:2408196@sipproxy.mydomain.com Call-ID: 252eb142-ae30-30f0-803c-0002a400f1e9@192.168.0.191 CSeq: 30 CANCEL Date: Thu, 16 Jun 2005 07:45:57 GMT User-Agent: AddPac SIP Gateway Content-Length: 0 Max-Forwards: 70

# U xx.xx.154.35:5060 -> xx.xx.148.231:5060 CANCEL sip:7072408196@xx.xx.148.231:5060 SIP/2.0 Record-Route: sip:2408196@xx.xx.154.35;ftag=2542303ca4;lr=on Via: SIP/2.0/UDP xx.xx.154.35;branch=z9hG4bKe6c7.e2501f15.0 Via: SIP/2.0/UDP 192.168.0.191:5060;received=xx.xx.148.244;branch=z9hG4bK2542303ca430 From: sip:5555848110@sipproxy.mydomain.com;tag=2542303ca4 To: sip:2408196@sipproxy.mydomain.com Call-ID: 252eb142-ae30-30f0-803c-0002a400f1e9@192.168.0.191 CSeq: 30 CANCEL Date: Thu, 16 Jun 2005 07:45:57 GMT User-Agent: AddPac SIP Gateway Content-Length: 0 Max-Forwards: 69 P-hint: H323-Side

# U xx.xx.154.35:5060 -> xx.xx.148.244:5060 SIP/2.0 200 cancelling Via: SIP/2.0/UDP 192.168.0.191:5060;branch=z9hG4bK2542303ca430;received=xx.xx.148.244 From: sip:5555848110@sipproxy.mydomain.com;tag=2542303ca4 To: sip:2408196@sipproxy.mydomain.com;tag=8acf748d21b6bc66e44e951325ba3f1c-b28 c Call-ID: 252eb142-ae30-30f0-803c-0002a400f1e9@192.168.0.191 CSeq: 30 CANCEL Server: Sip EXpress router (0.8.14-3 (i386/linux)) Content-Length: 0 Warning: 392 xx.xx.154.35:5060 "Noisy feedback tells: pid=23757 req_src_ip=xx.xx.148.244 req_src_port=64435 in_uri=sip:2408196@sipproxy.mydomain.com out_uri=sip:7072408196@xx.xx.148.231:5060 via_cnt==1"

This cause a endless CANCEL message flow coming from my endpoint.

Hope that someone can help me here Thanks in advance Best Regards

Ricardo Martinez