F5 looping SIP ACK packet over and over
F5 sending ACK over and over to SIP proxy server in response of 200 OK and later after max out request SIP Proxy dropping packets, it's very strange behavior, following is pcap of SIP request. You can see in last 3 ACK (there are many but i capture only 3 for this question) 70.xx.xx.202 - SNAT IP 70.xx.xx.180 - VIP Address 70.xx.xx.29 - SIP Server U 70.xx.xx.29:5060 -> 70.xx.xx.202:4371 SIP/2.0 100 trying -- your call is important to us. Via: SIP/2.0/UDP 10.0.30.101:5060;branch=z9hG4bK-38590-1-0;rport=4371;received=70.xx.xx.202. From: "anon" ;tag=38590SIPpTag001. To: service . Call-ID: 1-38590@10.0.30.101. CSeq: 1 INVITE. Content-Length: 0. . U 70.xx.xx.29:5060 -> 70.xx.xx.202:4371 SIP/2.0 200 OK. Record-Route: . Via: SIP/2.0/UDP 10.0.30.101:5060;rport=4371;received=70.xx.xx.202;branch=z9hG4bK-38590-1-0. From: "anon" ;tag=38590SIPpTag001. To: service ;tag=a6a1c5f60faecf035a1ae5b6e96e979a-3c64. Call-ID: 1-38590@10.0.30.101. CSeq: 1 INVITE. Record-Route: . Content-Type: application/sdp. Contact: . Content-Length: 321. P-hint: DIRECT-RTP. . v=0. o=- 3705165012 3705165012 IN IP4 74.xx.xx.28. s=session. c=IN IP4 74.xx.xx.28. t=0 0. m=audio 18424 RTP/AVP 0. a=rtpmap:0 PCMU/8000. a=sp_media_cookie:4ac9631c1f904ac9631c1f9a014ac9631c47f8. a=candidate 900568881 1 pas900568881 UDP 1.0 74.xx.xx.28 18424. a=sp_chan_type:echo. a=sp_max_gain:1.700000. a=sp_rtcp:0. U 70.xx.xx.202:4371 -> 70.xx.xx.29:5060 ACK sip:service@70.xx.xx.180:5060 SIP/2.0. Via: SIP/2.0/UDP 10.0.30.101:5060;branch=z9hG4bK-38590-1-5. From: "anon" ;tag=38590SIPpTag001. To: service ;tag=a6a1c5f60faecf035a1ae5b6e96e979a-3c64. Call-ID: 1-38590@10.0.30.101. CSeq: 1 ACK. Contact: sip:.anon.@10.0.30.101:5060. Max-Forwards: 70. Subject: Performance Test. Content-Length: 0. P-hint: PROXY-RTP.. Record-Route: . . U 70.xx.xx.202:8553 -> 70.xx.xx.29:5060 ACK sip:service@70.xx.xx.180:5060 SIP/2.0. Record-Route: . Record-Route: . Via: SIP/2.0/UDP 70.xx.xx.29:5060;branch=0. Via: SIP/2.0/UDP 10.0.30.101:5060;rport=4371;received=70.xx.xx.202;branch=z9hG4bK-38590-1-5. From: "anon" ;tag=38590SIPpTag001. To: service ;tag=a6a1c5f60faecf035a1ae5b6e96e979a-3c64. Call-ID: 1-38590@10.0.30.101. CSeq: 1 ACK. Contact: sip:.anon.@70.xx.xx.202:4371. Max-Forwards: 16. Subject: Performance Test. Content-Length: 0. P-hint: PROXY-RTP.. Record-Route: . P-hint: PROXY-RTP. P-hint: NON-LOCAL. . U 70.xx.xx.202:8553 -> 70.xx.xx.29:5060 ACK sip:service@70.xx.xx.180:5060 SIP/2.0. Record-Route: . Record-Route: . Record-Route: . Record-Route: . Via: SIP/2.0/UDP 70.xx.xx.29:5060;branch=0. Via: SIP/2.0/UDP 70.xx.xx.29:5060;rport=8553;received=70.xx.xx.202;branch=0. Via: SIP/2.0/UDP 10.0.30.101:5060;rport=4371;received=70.xx.xx.202;branch=z9hG4bK-38590-1-5. From: "anon" ;tag=38590SIPpTag001. To: service ;tag=a6a1c5f60faecf035a1ae5b6e96e979a-3c64. Call-ID: 1-38590@10.0.30.101. CSeq: 1 ACK. Contact: sip:.anon.@70.xx.xx.202:8553. Max-Forwards: 15. Subject: Performance Test. Content-Length: 0. P-hint: PROXY-RTP.. Record-Route: . P-hint: PROXY-RTP. P-hint: NON-LOCAL. P-hint: PROXY-RTP. P-hint: NON-LOCAL.