I am trying to debug a SIP issue, between an Asterisk 1.2.32 system that is behind a network device to which I don't have ready access, which is performing NAT with possibly some kind of SIP ALG, and an Asterisk 11 system on a public IP.
My question is very specific, and I don't need right now to discuss the ins and outs of the above setup. What I am seeing is that when I have set up a call from the Asterisk 11 system, the 1.2.32 system is sending 200 OK, and sip debug shows the ACK response coming back from the Asterisk 11 box. However, the ACK appears not to be understood, because the 200 OK gets re-sent, multiple times, and eventually gives up. My specific question is, what values in the ACK does chan_sip (1.2.32) use to match the ACK with the pending 200 OK? My understanding of the chan_sip.c code is not good enough to work it out for certain. Here is the 200 OK (I've changed the address of the public endpoint): Mar 30 10:20:20 VERBOSE[5811] logger.c: Retransmitting #5 (no NAT) to 11.111.11.111:5060: SIP/2.0 200 OK Via: SIP/2.0/UDP 11.111.11.111:5060;branch=z9hG4bK6bee4b53;received=11.111.11.111 From: "Tony Mountifield" <sip:[email protected]>;tag=as4ab948f7 To: <sip:[email protected]>;tag=as76e64309 Call-ID: [email protected]:5060 CSeq: 102 INVITE User-Agent: Asterisk PBX Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Contact: <sip:[email protected]> Content-Type: application/sdp Content-Length: 218 v=0 o=root 5732 5732 IN IP4 172.16.141.143 s=session c=IN IP4 172.16.141.143 t=0 0 m=audio 16282 RTP/AVP 0 101 a=rtpmap:0 PCMU/8000 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=silenceSupp:off - - - - And here is the ACK in reply that is not getting understood: <-- SIP read from 11.111.11.111:5060: ACK sip:[email protected] SIP/2.0 Via: SIP/2.0/UDP 11.111.11.111:5060;branch=z9hG4bK36651b68 Max-Forwards: 70 From: "Tony Mountifield" <sip:[email protected]>;tag=as4ab948f7 To: <sip:[email protected]>;tag=as76e64309 Contact: <sip:[email protected]:5060> Call-ID: [email protected]:5060 CSeq: 102 ACK User-Agent: Asterisk PBX 11.5.0 Content-Length: 0 So what is it about the ACK that is wrong? Thanks for any help! Cheers Tony -- Tony Mountifield Work: [email protected] - http://www.softins.co.uk Play: [email protected] - http://tony.mountifield.org -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
