root@comcerto:~# tcpdump -v -s1514 port 5060 and host 172.16.200.70 tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 1514 bytes 04:37:46.042690 IP (tos 0xa,ECT(0), ttl 61, id 32165, offset 0, flags [DF], proto UDP (17), length 372) 172.16.200.70.5060 > 172.16.110.11.5060: SIP, length: 344 OPTIONS sip:172.16.110.11:5060 SIP/2.0 Via: SIP/2.0/UDP 172.16.200.70:5060;branch=z9hG4bK_a3Kr_1763094650839X0006D56E To: From: ;tag=1763094650000764B2 Contact: Call-ID: 6916B07ACCE0E0006D468_172.16.200.70 CSeq: 100 OPTIONS Max-Forwards: 70 Content-Length: 0 04:37:46.054527 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 343) 172.16.110.11.5060 > 172.16.200.70.5060: SIP, length: 315 SIP/2.0 200 OK Via: SIP/2.0/UDP 172.16.200.70:5060;branch=z9hG4bK_a3Kr_1763094650839X0006D56E Contact: To: ;tag=9148de3b From: ;tag=1763094650000764B2 Call-ID: 6916B07ACCE0E0006D468_172.16.200.70 CSeq: 100 OPTIONS Content-Length: 0 04:37:47.263918 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 1265) 172.16.110.11.5060 > 172.16.200.70.5060: SIP, length: 1237 INVITE sip:36901@172.16.200.70:5060;user=phone SIP/2.0 Via: SIP/2.0/UDP 172.16.110.11:5060;branch=z9hG4bK-524287-1---d3ca871b30386064;rport Via: SIP/2.0/UDP 172.16.100.70:5060;branch=z9hG4bK-t8dy9-xwifp Max-Forwards: 69 Record-Route: 04:37:47.268802 IP (tos 0xa,ECT(0), ttl 61, id 32343, offset 0, flags [DF], proto UDP (17), length 554) 172.16.200.70.5060 > 172.16.110.11.5060: SIP, length: 526 SIP/2.0 100 Trying Via: SIP/2.0/UDP 172.16.110.11:5060;received=172.16.110.11;branch=z9hG4bK-524287-1---d3ca871b30386064;rport=5060 Via: SIP/2.0/UDP 172.16.100.70:5060;branch=z9hG4bK-t8dy9-xwifp Record-Route: To: ;tag=1763094652000764B3 From: ;tag=74fn44keqh Contact: Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 189 INVITE Content-Length: 0 04:37:47.423803 IP (tos 0xa,ECT(0), ttl 61, id 32345, offset 0, flags [DF], proto UDP (17), length 845) 172.16.200.70.5060 > 172.16.110.11.5060: SIP, length: 817 SIP/2.0 180 Ringing Via: SIP/2.0/UDP 172.16.110.11:5060;received=172.16.110.11;branch=z9hG4bK-524287-1---d3ca871b30386064;rport=5060 Via: SIP/2.0/UDP 172.16.100.70:5060;branch=z9hG4bK-t8dy9-xwifp Record-Route: To: ;tag=1763094652000764B3 From: ;tag=74fn44keqh Contact: Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 189 INVITE Allow: INVITE,CANCEL,ACK,BYE,INFO,PRACK,UPDATE,NOTIFY,MESSAGE,REFER,OPTIONS Session-ID: c35208d08a9b4ead8058fbe8e3230c0f Content-Type: application/sdp Content-Length: 134 v=0 o=mkd 1763094525 1 IN IP4 172.16.200.70 s=protei c=IN IP4 172.16.200.70 t=0 0 m=audio 21548 RTP/AVP 8 a=rtpmap:8 PCMA/8000 04:37:50.161107 IP (tos 0xa,ECT(0), ttl 61, id 32803, offset 0, flags [DF], proto UDP (17), length 840) 172.16.200.70.5060 > 172.16.110.11.5060: SIP, length: 812 SIP/2.0 200 OK Via: SIP/2.0/UDP 172.16.110.11:5060;received=172.16.110.11;branch=z9hG4bK-524287-1---d3ca871b30386064;rport=5060 Via: SIP/2.0/UDP 172.16.100.70:5060;branch=z9hG4bK-t8dy9-xwifp Record-Route: To: ;tag=1763094652000764B3 From: ;tag=74fn44keqh Contact: Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 189 INVITE Allow: INVITE,CANCEL,ACK,BYE,INFO,PRACK,UPDATE,NOTIFY,MESSAGE,REFER,OPTIONS Session-ID: c35208d08a9b4ead8058fbe8e3230c0f Content-Type: application/sdp Content-Length: 134 v=0 o=mkd 1763094525 1 IN IP4 172.16.200.70 s=protei c=IN IP4 172.16.200.70 t=0 0 m=audio 21548 RTP/AVP 8 a=rtpmap:8 PCMA/8000 04:37:50.188243 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 516) 172.16.110.11.5060 > 172.16.200.70.5060: SIP, length: 488 ACK sip:36901@172.16.200.70:5060 SIP/2.0 Via: SIP/2.0/UDP 172.16.110.11:5060;branch=z9hG4bK-524287-1---09d2b77f8d3d781d;rport Via: SIP/2.0/UDP 172.16.100.70:5060;branch=z9hG4bK-qe79s-1uyc7 Max-Forwards: 69 To: ;tag=1763094652000764B3 04:37:50.191107 IP (tos 0xa,ECT(0), ttl 61, id 32810, offset 0, flags [DF], proto UDP (17), length 828) 172.16.200.70.5060 > 172.16.110.11.5060: SIP, length: 800 INVITE sip:31189@172.16.100.70:5060;user=phone SIP/2.0 Via: SIP/2.0/UDP 172.16.200.70:5060;branch=z9hG4bK_a3Kr_1763094654987X0006D572 Route: To: ;tag=74fn44keqh From: ;tag=1763094652000764B3 Contact: Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 1000 INVITE Max-Forwards: 70 Allow: INVITE,CANCEL,ACK,BYE,INFO,PRACK,UPDATE,NOTIFY,MESSAGE,REFER,OPTIONS Content-Type: application/sdp Content-Length: 214 v=0 o=mkd 1763094525 2 IN IP4 172.29.100.21 s=protei c=IN IP4 172.29.100.21 t=0 0 m=audio 12428 RTP/AVP 8 101 a=rtpmap:8 PCMA/8000 a=ptime:20 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=sendrecv 04:37:50.207223 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 540) 172.16.110.11.5060 > 172.16.200.70.5060: SIP, length: 512 SIP/2.0 407 Proxy Authentication Required Via: SIP/2.0/UDP 172.16.200.70:5060;branch=z9hG4bK_a3Kr_1763094654987X0006D572 Proxy-Authenticate: Digest nonce="1763095070:7476a641db183155682c4364acc5d0dd",algorithm=MD5,realm="172.16.110.11",qop="auth,auth-int" To: ;tag=74fn44keqh From: ;tag=1763094652000764B3 Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 1000 INVITE Server: repro 1.12.0 Content-Length: 0 04:37:50.211122 IP (tos 0xa,ECT(0), ttl 61, id 32812, offset 0, flags [DF], proto UDP (17), length 407) 172.16.200.70.5060 > 172.16.110.11.5060: SIP, length: 379 ACK sip:31189@172.16.100.70:5060;user=phone SIP/2.0 Via: SIP/2.0/UDP 172.16.200.70:5060;branch=z9hG4bK_a3Kr_1763094654987X0006D572 To: ;tag=74fn44keqh From: ;tag=1763094652000764B3 Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 1000 ACK Max-Forwards: 70 Content-Length: 0 04:37:50.212178 IP (tos 0xa,ECT(0), ttl 61, id 32813, offset 0, flags [DF], proto UDP (17), length 481) 172.16.200.70.5060 > 172.16.110.11.5060: SIP, length: 453 BYE sip:31189@172.16.100.70:5060;user=phone SIP/2.0 Via: SIP/2.0/UDP 172.16.200.70:5060;branch=z9hG4bK_a3Kr_1763094655008X0006D573 Route: To: ;tag=74fn44keqh From: ;tag=1763094652000764B3 Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 1001 BYE Max-Forwards: 70 Reason: Q.850;cause=34 Content-Length: 0 04:37:50.243631 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 374) 172.16.110.11.5060 > 172.16.200.70.5060: SIP, length: 346 SIP/2.0 200 OK Via: SIP/2.0/UDP 172.16.200.70:5060;branch=z9hG4bK_a3Kr_1763094655008X0006D573 To: ;tag=74fn44keqh From: ;tag=1763094652000764B3 Call-ID: ff46ca58ayt3eyh8npg@172.16.100.70 CSeq: 1001 BYE Server: repro 1.12.0 Content-Length: 0 12 packets captured 13 packets received by filter 0 packets dropped by kernel root@comcerto:~#