[root@server1 ~]# tcpdump -nqt -s 0 -A -vvv -i eth0 port 5060
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
IP (tos 0x0, ttl 47, id 32975, offset 0, flags [DF], proto TCP (6), length 1398)
    92.40.248.63.60674 > 162.248.6.120.sip: tcp 1346
E..v..@./...\(.?...n....xC.....>...R.......
..WC.Y..INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP 10.180.107.181:49409;branch=z9hG4bK.igYvCrxm9;rport
From: <sip:[email protected]>;tag=giH~dQzPe
To: sip:[email protected]
CSeq: 20 INVITE
Call-ID: PX~xTBPTJp
Max-Forwards: 70
Supported: outbound
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY, MESSAGE, SUBSCRIBE, INFO, UPDATE
Content-Type: application/sdp
Content-Length: 876
Contact: <sip:[email protected]:60674;transport=tcp>;+sip.instance="<urn:uuid:e0cfe3fc-7eda-4a83-8be6-545a5bf10d8c>"
User-Agent: LinphoneAndroid/2599 (belle-sip/1.4.2)

v=0
o=1111 996 1600 IN IP4 10.180.107.181
s=Talk
c=IN IP4 10.180.107.181
b=AS:380
t=0 0
a=ice-pwd:4e336474a38785edb40f3023
a=ice-ufrag:8c946eb2
a=rtcp-xr:rcvr-rtt=all:10000 stat-summary=loss,dup,jitt,TTL voip-metrics
m=audio 51755 RTP/AVP 96 97 98 99 0 8 101 100 102
c=IN IP4 92.40.248.63
a=rtpmap:96 opus/48000/2
a=fmtp:96 useinbandfec=1
a=rtpmap:97 SILK/16000
a=rtpmap:98 speex/16000
a=fmtp:98 vbr=on
a=rtpmap:99 speex/8000
a=fmtp:99 vbr=on
a=rtpmap:101 telephone-event/48000
a=rtpmap:100 telephone-event/16000
a=rtpmap:102 telephone-event/8000
a=candidate:1 1 UDP 2130706431 10.180.107.181 7076 typ host
a=candidate:1 2 UDP 2130706430 10.180.107.181 7077 typ host
a=candidate:2 1 UDP 1694498815 92.40.248.63 51755 typ srflx raddr 10.180.107.181
IP (tos 0x0, ttl 47, id 32976, offset 0, flags [DF], proto TCP (6), length 157)
    92.40.248.63.60674 > 162.248.6.120.sip: tcp 105
E.....@./...\(.?...n....xC.....>...R.......
..WC.Y..rport 7076
a=candidate:2 2 UDP 1694498814 92.40.248.63 51756 typ srflx raddr 10.180.107.181 rport 7077

IP (tos 0x10, ttl 64, id 36487, offset 0, flags [DF], proto TCP (6), length 52)
    162.248.6.120.sip > 92.40.248.63.60674: tcp 0
E..4..@.@..]...n\(.?.......>xC.7...........
.Z.|..WC
IP (tos 0x10, ttl 64, id 36488, offset 0, flags [DF], proto TCP (6), length 350)
    162.248.6.120.sip > 92.40.248.63.60674: tcp 298
E..^..@[email protected]\(.?.......>xC.7...........
.Z.|..WCSIP/2.0 100 Giving a try
Via: SIP/2.0/TCP 10.180.107.181:49409;received=92.40.248.63;branch=z9hG4bK.igYvCrxm9;rport=60674
From: <sip:[email protected]>;tag=giH~dQzPe
To: sip:[email protected]
CSeq: 20 INVITE
Call-ID: PX~xTBPTJp
Server: OpenSIPS (2.1.1 (x86_64/linux))
Content-Length: 0


IP (tos 0x0, ttl 47, id 32977, offset 0, flags [DF], proto TCP (6), length 52)
    92.40.248.63.60674 > 162.248.6.120.sip: tcp 0
E..4..@./..#\(.?...n....xC.7...h...W_^.....
..WR.Z.|
IP (tos 0x10, ttl 64, id 36489, offset 0, flags [DF], proto TCP (6), length 395)
    162.248.6.120.sip > 92.40.248.63.60674: tcp 343
E.....@[email protected]\(.?.......hxC.7.....L.....
.Z....WRSIP/2.0 408 Request Timeout
Via: SIP/2.0/TCP 10.180.107.181:49409;received=92.40.248.63;branch=z9hG4bK.igYvCrxm9;rport=60674
From: <sip:[email protected]>;tag=giH~dQzPe
To: sip:[email protected];tag=364660755d8ca6c0205a1abd0319a354-66c5
CSeq: 20 INVITE
Call-ID: PX~xTBPTJp
Server: OpenSIPS (2.1.1 (x86_64/linux))
Content-Length: 0


IP (tos 0x0, ttl 47, id 32978, offset 0, flags [DF], proto TCP (6), length 52)
    92.40.248.63.60674 > 162.248.6.120.sip: tcp 0
E..4..@./.."\(.?...n....xC.7.......\Gv.....
..Y_.Z..
IP (tos 0x0, ttl 47, id 32979, offset 0, flags [DF], proto TCP (6), length 468)
    92.40.248.63.60674 > 162.248.6.120.sip: tcp 416
E.....@./...\(.?...n....xC.7.......\.......
..Ya.Z..ACK sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP 10.180.107.181:49409;branch=z9hG4bK.igYvCrxm9;rport
Call-ID: PX~xTBPTJp
From: <sip:[email protected]>;tag=giH~dQzPe
To: <sip:[email protected]>;tag=364660755d8ca6c0205a1abd0319a354-66c5
Contact: <sip:[email protected]:60674;transport=tcp>;+sip.instance="<urn:uuid:e0cfe3fc-7eda-4a83-8be6-545a5bf10d8c>"
Max-Forwards: 70
CSeq: 20 ACK
Content-Length: 0


IP (tos 0x10, ttl 64, id 36490, offset 0, flags [DF], proto TCP (6), length 52)
    162.248.6.120.sip > 92.40.248.63.60674: tcp 0
E..4..@[email protected]\(.?........xC.............
.Z....Ya
^C
9 packets captured
9 packets received by filter
0 packets dropped by kernel