Below are some SIP snippets from both a successful call and a failed call:
Successful call from External (Internet) UA to Internal UA behind same NAT router as Kamailio server
Frame 77 (External UA Caller to Kamailio Server) Session Initiation Protocol (INVITE) Request-Line: INVITE sip:wow@pub-domain-name.net SIP/2.0 Method: INVITE Request-URI: sip:wow@pub-domain-name.net [Resent Packet: False] Message Header Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0 [Generated Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0] CSeq: 2 INVITE Sequence Number: 2 Method: INVITE From: "Think" sip:think@pub-domain-name.net;tag=da48a35 SIP from display info: "Think" SIP from address: sip:think@pub-domain-name.net SIP from tag: da48a35 To: sip:wow@pub-domain-name.net SIP to address: sip:wow@pub-domain-name.net Max-Forwards: 70 Contact: "Think" sip:think@192.168.9.150:49872;transport=tcp;registering_acc=pub-domain-net_net User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Via: SIP/2.0/TCP 192.168.9.150:49872;branch=z9hG4bK-363937-300d55dbdefe8ad301c7961b7c4c0e8a Proxy-Authorization: Digest username="think",realm="pub-domain-name.net",nonce="aHqfVWh6nikvR+zIKjSHaJPKD8Hlgooy",uri="sip:wow@pub-domain-name.net",response="b7d5db659208fcbfdd3b441e869bc253" Content-Length: 550 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): think-jitsi.org 0 0 IN IP4 192.168.9.150 Session Name (s): - Connection Information (c): IN IP4 192.168.9.150
Frame 80 (Kamailio Server to Internal UA callee; external UA public ip address added to Contact header as alias) Session Initiation Protocol (INVITE) Request-Line: INVITE sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net SIP/2.0 Method: INVITE Request-URI: sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net [Resent Packet: False] Message Header Record-Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0 [Generated Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0] CSeq: 2 INVITE Sequence Number: 2 Method: INVITE From: "Think" sip:think@pub-domain-name.net;tag=da48a35 SIP from display info: "Think" SIP from address: sip:think@pub-domain-name.net SIP from tag: da48a35 To: sip:wow@pub-domain-name.net SIP to address: sip:wow@pub-domain-name.net Max-Forwards: 69 Contact: "Think" sip:think@192.168.9.150:49872;transport=tcp;registering_acc=pub-domain-net_net;alias=172.59.210.229~28301~2 SIP C-URI display info: "Think" Contact URI: sip:think@192.168.9.150:49872;transport=tcp;registering_acc=pub-domain-net_net;alias=172.59.210.229~28301~2 User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Via: SIP/2.0/TCP pub-domain-name.net:5060;branch=z9hG4bK5818.37b0c4a1d32535a805caaa6cc7d97071.0;i=6 Via: SIP/2.0/TCP 192.168.9.150:49872;rport=28301;received=172.59.210.229;branch=z9hG4bK-363937-300d55dbdefe8ad301c7961b7c4c0e8a Content-Length: 594 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): think-jitsi.org 0 0 IN IP4 73.150.xxx.xxx Session Name (s): - Connection Information (c): IN IP4 73.150.xxx.xxx
Frame 91 (Internal UA callee to Kamailio Server: 200-OK) Session Initiation Protocol (200) Status-Line: SIP/2.0 200 OK Status-Code: 200 [Resent Packet: False] [Request Frame: 80] [Response Time (ms): 4837] Message Header CSeq: 2 INVITE Sequence Number: 2 Method: INVITE Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0 [Generated Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0] From: "Think" sip:think@pub-domain-name.net;tag=da48a35 SIP from display info: "Think" SIP from address: sip:think@pub-domain-name.net SIP from tag: da48a35 To: sip:wow@pub-domain-name.net;tag=a160389a SIP to address: sip:wow@pub-domain-name.net SIP to tag: a160389a […]Via: SIP/2.0/TCP pub-domain-name.net:5060;branch=z9hG4bK5818.37b0c4a1d32535a805caaa6cc7d97071.0;i=6;received=73.150.xxx.xxx;rport=5060,SIP/2.0/TCP 192.168.9.150:49872;rport=28301;received=172.59.210.229;branch=z9hG4bK-363937-300d55d Record-Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Contact: "wow" sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net SIP C-URI display info: "wow" Contact URI: sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Content-Length: 546 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): wow-jitsi.org 0 0 IN IP4 192.168.2.13 Session Name (s): - Connection Information (c): IN IP4 192.168.2.13 Connection Network Type: IN Connection Address Type: IP4 Connection Address: 192.168.2.13 Time Description, active time (t): 0 0 Media Description, name and address (m): audio 5000 RTP/AVP 96
Frame 92 (Kamailio server to External UA caller: 200-OK) Session Initiation Protocol (200) Status-Line: SIP/2.0 200 OK Status-Code: 200 [Resent Packet: False] [Request Frame: 77] [Response Time (ms): 4893] Message Header CSeq: 2INVITE Sequence Number: 2 Method: INVITE Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0 [Generated Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0] From: "Think" sip:think@pub-domain-name.net;tag=da48a35 SIP from display info: "Think" SIP from address: sip:think@pub-domain-name.net SIP from tag: da48a35 To: sip:wow@pub-domain-name.net;tag=a160389a SIP to address: sip:wow@pub-domain-name.net SIP to tag: a160389a Via: SIP/2.0/TCP 192.168.9.150:49872;rport=28301;received=172.59.210.229;branch=z9hG4bK-363937-300d55dbdefe8ad301c7961b7c4c0e8a Record-Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Contact: "wow" sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net SIP C-URI display info: "wow" Contact URI: sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Content-Length: 1182 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): wow-jitsi.org 0 0 IN IP4 73.150.xxx.xxx Session Name (s): - Connection Information (c): IN IP4 73.150.xxx.xxx Connection Network Type: IN Connection Address Type: IP4 Connection Address: 73.150.xxx.xxx Time Description, active time (t): 0 0 Media Description, name and address (m): audio 35010 RTP/AVP 96
Frame 95 (External Caller UA to Kamailio Server: ACK of 200-OK) Session Initiation Protocol (ACK) Request-Line: ACK sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net SIP/2.0 Method: ACK Request-URI: sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net [Resent Packet: False] [Request Frame: 77] [Response Time (ms): 5144] Message Header Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0 [Generated Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0] CSeq: 2 ACK Sequence Number: 2 Method: ACK Via: SIP/2.0/TCP 192.168.9.150:49872;branch=z9hG4bK-363937-acd86ef1272918c02f80646a7ffd32c3 From: "Think" sip:think@pub-domain-name.net;tag=da48a35 SIP from display info: "Think" SIP from address: sip:think@pub-domain-name.net SIP from tag: da48a35 To: "wow" sip:wow@pub-domain-name.net;tag=a160389a SIP to display info: "wow" SIP to address: sip:wow@pub-domain-name.net SIP to tag: a160389a Max-Forwards: 70 Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Contact: "Think" sip:think@192.168.9.150:49872;transport=tcp;registering_acc=pub-domain-net_net SIP C-URI display info: "Think" Contact URI: sip:think@192.168.9.150:49872;transport=tcp;registering_acc=pub-domain-net_net User-Agent: Jitsi2.10.5550Windows 10 Content-Length: 0
Frame 96 (Kamailio Server to Internal UA: ACK of 200-OK) Session Initiation Protocol (ACK) Request-Line: ACK sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net SIP/2.0 Method: ACK Request-URI: sip:wow@192.168.2.13:50060;transport=tcp;registering_acc=pub-domain-net_net [Resent Packet: False] [Request Frame: 80] [Response Time (ms): 5101] Message Header Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0 [Generated Call-ID: 5130c2963b8c1f46de2aa92e5ff3dee7@0:0:0:0:0:0:0:0] CSeq: 2 ACK Sequence Number: 2 Method: ACK Via: SIP/2.0/TCP pub-domain-name.net:5060;branch=z9hG4bK5818.98ab28cca407d8483ad6a69389305265.0;i=6 Via: SIP/2.0/TCP 192.168.9.150:49872;rport=28301;received=172.59.210.229;branch=z9hG4bK-363937-acd86ef1272918c02f80646a7ffd32c3 From: "Think" sip:think@pub-domain-name.net;tag=da48a35 SIP from display info: "Think" SIP from address: sip:think@pub-domain-name.net SIP from tag: da48a35 To: "wow" sip:wow@pub-domain-name.net;tag=a160389a SIP to display info: "wow" SIP to address: sip:wow@pub-domain-name.net SIP to tag: a160389a Max-Forwards: 69 Contact: "Think" sip:think@192.168.9.150:49872;transport=tcp;registering_acc=pub-domain-net_net;alias=172.59.210.229~28301~2 SIP C-URI display info: "Think" Contact URI: sip:think@192.168.9.150:49872;transport=tcp;registering_acc=pub-domain-net_net;alias=172.59.210.229~28301~2 User-Agent: Jitsi2.10.5550Windows 10 Content-Length: 0 RTP Connection finalized and succesful call is made.
Failed Call: Frame 58 (Int->Ext UA Caller Invite to Kamailio Server) Session Initiation Protocol (INVITE) Request-Line: INVITE sip:think@pub-domain-name.net SIP/2.0 Method: INVITE Request-URI: sip:think@pub-domain-name.net [Resent Packet: False] Message Header Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0 [Generated Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0] CSeq: 2 INVITE From: "WOW" sip:wow@pub-domain-name.net;tag=b1fd2e81 To: sip:think@pub-domain-name.net Max-Forwards: 70 Contact: "WOW" sip:wow@192.168.2.13:53616;transport=tcp;registering_acc=pub-domain-name_net User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Via: SIP/2.0/TCP 192.168.2.13:53616;branch=z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Transport: TCP Sent-by Address: 192.168.2.13 Sent-by port: 53616 Branch: z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Proxy-Authorization: Digest username="wow",realm="pub-domain-name.net",nonce="aIE222iBNa9LWBxxscVnnbDdGK4JO0FZ",uri="sip:think@pub-domain-name.net",response="29a3edef773fdde72fe0d462f827f35f" Content-Length: 890 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): wow-jitsi.org 0 0 IN IP4 192.168.2.13 Session Name (s): - Connection Information (c): IN IP4 192.168.2.13 Time Description, active time (t): 0 0 Media Description, name and address (m): audio 5000 RTP/AVP 96 97 98 9 100 102 0 8 103 3 104 101
Frame 61 (Int->Ext Call - Kamailio to External UA) Session Initiation Protocol (INVITE) Request-Line: INVITE sip:think@192.168.6.129:62162;transport=tcp;registering_acc=pub-domain-name_net SIP/2.0 Method: INVITE Request-URI: sip:think@192.168.6.129:62162;transport=tcp;registering_acc=pub-domain-name_net [Resent Packet: False] Message Header Record-Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0 [Generated Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0] CSeq: 2 INVITE From: "WOW" sip:wow@pub-domain-name.net;tag=b1fd2e81 To: sip:think@pub-domain-name.net Max-Forwards: 69 Contact: "WOW" sip:wow@192.168.2.13:53616;transport=tcp;registering_acc=pub-domain-name_net;alias=192.168.2.13~53616~2 User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Via: SIP/2.0/TCP pub-domain-name.net:5060;branch=z9hG4bK21a9.589fa94c2a5f6bf663ed3ab3f2c76f52.0;i=1 Transport: TCP Sent-by Address: pub-domain-name.net Sent-by port: 5060 Branch: z9hG4bK21a9.589fa94c2a5f6bf663ed3ab3f2c76f52.0 i=1 Via: SIP/2.0/TCP 192.168.2.13:53616;rport=53616;branch=z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Transport: TCP Sent-by Address: 192.168.2.13 Sent-by port: 53616 RPort: 53616 Branch: z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Content-Length: 936 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): wow-jitsi.org 0 0 IN IP4 73.150.xxx.xxx Session Name (s): - Connection Information (c): IN IP4 73.150.xxx.xxx Time Description, active time (t): 0 0 Media Description, name and address (m): audio 35000 RTP/AVP 96 97 98 9 100 102 0 8 103 3 104 101
Frame 84 (External Callee to Kamailio Server: 200-OK) Session Initiation Protocol (200) Status-Line: SIP/2.0 200 OK Status-Code: 200 [Resent Packet: False] Message Header CSeq: 2 INVITE Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0 [Generated Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0] From: "WOW" sip:wow@pub-domain-name.net;tag=b1fd2e81 To: sip:think@pub-domain-name.net;tag=1186416 Via: SIP/2.0/TCP pub-domain-name.net:5060;branch=z9hG4bK21a9.589fa94c2a5f6bf663ed3ab3f2c76f52.0;i=1;received=73.150.xxx.xxx;rport=5060,SIP/2.0/TCP 192.168.2.13:53616;rport=53616;branch=z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Transport: TCP Sent-by Address: pub-domain-name.net Sent-by port: 5060 Branch: z9hG4bK21a9.589fa94c2a5f6bf663ed3ab3f2c76f52.0 i=1 Received: 73.150.xxx.xxx RPort: 5060 Transport: TCP Sent-by Address: 192.168.2.13 Sent-by port: 53616 RPort: 53616 Branch: z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Record-Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Contact: "Think" sip:think@192.168.6.129:62162;transport=tcp;registering_acc=pub-domain-name_net User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Content-Length: 556 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): think-jitsi.org 0 0 IN IP4 192.168.6.129 Session Name (s): - Connection Information (c): IN IP4 192.168.6.129 Time Description, active time (t): 0 0 Media Description, name and address (m): audio 5000 RTP/AVP 103
Frame 86 (Kamailio to Internal Caller UA: 200-OK)
Session Initiation Protocol (200) Status-Line: SIP/2.0 200 OK Status-Code: 200 [Resent Packet: False] Message Header CSeq: 2 INVITE Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0 [Generated Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0] From: "WOW" sip:wow@pub-domain-name.net;tag=b1fd2e81 To: sip:think@pub-domain-name.net;tag=1186416 Via: SIP/2.0/TCP 192.168.2.13:53616;rport=53616;branch=z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Transport: TCP Sent-by Address: 192.168.2.13 Sent-by port: 53616 RPort: 53616 Branch: z9hG4bK-333030-96dd852a7c0145c94806d428bfd52f71 Record-Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Contact: "Think" sip:think@192.168.6.129:62162;transport=tcp;registering_acc=pub-domain-name_net User-Agent: Jitsi2.10.5550Windows 10 Content-Type: application/sdp Content-Length: 1223 Message Body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): think-jitsi.org 0 0 IN IP4 73.150.xxx.xxx Session Name (s): - Connection Information (c): IN IP4 73.150.xxx.xxx Time Description, active time (t): 0 0 Media Description, name and address (m): audio 35022 RTP/AVP 103 Media Description, name and address (m): audio 35066 RTP/AVP 103
Frame 136 (Internal caller UA sending SIP-ACK for 200-OK to Kamailio Server) Session Initiation Protocol (ACK) Request-Line: ACK sip:think@192.168.6.129:62162;transport=tcp;registering_acc=pub-domain-name_net SIP/2.0 Method: ACK Request-URI: sip:think@192.168.6.129:62162;transport=tcp;registering_acc=pub-domain-name_net [Resent Packet: False] Message Header Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0 [Generated Call-ID: 12e8162ae975b2a1b7cc2fed4101e962@0:0:0:0:0:0:0:0] CSeq: 2 ACK Via: SIP/2.0/TCP 192.168.2.13:53616;branch=z9hG4bK-333030-7fe73867b52851d45ac33961e1368312 Transport: TCP Sent-by Address: 192.168.2.13 Sent-by port: 53616 Branch: z9hG4bK-333030-7fe73867b52851d45ac33961e1368312 From: "WOW" sip:wow@pub-domain-name.net;tag=b1fd2e81 To: "Think" sip:think@pub-domain-name.net;tag=1186416 Max-Forwards: 70 Route: sip:pub-domain-name.net;transport=tcp;lr=on;nat=yes Contact: "WOW" sip:wow@192.168.2.13:53616;transport=tcp;registering_acc=pub-domain-name_net User-Agent: Jitsi2.10.5550Windows 10 Content-Length: 0
Kamailio Server sends a TCP ack back to internal UA caller but does not forward the SIP-response ACK to external UA callee -- NO RTP CONNECTION, CALL FAILS.