[SR-Users] Dialog missing when BYE is received from trunk

Hi all, I’ve got a call flow where PBX makes a call via Kamailio, which uses the UAC modules to make the call to the trunk. This works great, however I’ve noticed recently that when the BYE comes from the trunk, Kamailio doesn’t recognise the dialog and throws back a 404. Due to this, the PBX never knows the session has ended, and keeps its session open. Here’s the flow from Wireshark: https://i.imgur.com/BxPRrXP.png <https://i.imgur.com/BxPRrXP.png> As you can see, the BYE is received from the trunk, and Kamailio throws a 404. I checked with an rpc dlg.list and at this point the dialog had gone. 30 seconds later, I threw a BYE from the PBX, and because the dialog no longer existed, it got a 481 back. The INVITE to the trunk has the following Record-Route header: Record-Route: <sip:kamailio.public-ip;lr;ftag=mjKtcKaBteQ4Q;vst=AAAAAAYFBQUHAwYHBgRzMwIRGRMcAgJBWBEVCwAbBhtADxBjdGVkLmNvbS5hdQ--;did=624.b2e1> When the first BYE comes in, it still has same did in the Route header. Below I’ve put the output from the dialog list rpc call (before the first BYE) and the relevant log lines. { h_entry: 1062 h_id: 7723 ref: 2 call-id: a9d32620-2b68-1238-048a-0cc47a18705a from_uri: sip:61400123123@pbx.local:5060 to_uri: sip:61400123123@10.0.0.2 state: 4 start_ts: 1564269942 init_ts: 1564269929 end_ts: 0 timeout: 1564313142 lifetime: 43200 dflags: 643 sflags: 0 iflags: 16 caller: { tag: mjKtcKaBteQ4Q contact: sip:pbx.local cseq: 7581172 route_set: socket: udp:10.0.0.2:5060 } callee: { tag: SD5ptp899-1177933201-1564269931305 contact: sip:SDd3mt8-nn9jnirnmqcrvfmvkpm0hmhvgggjgv2io788of70s84u9@trunk.remote:5060;transport=udp cseq: 0 route_set: socket: udp:10.0.0.2:5060 } profiles: { } variables: { { cseq_diff: 1 } } } Jul 28 09:27:30 ip-10-0-0-2 /usr/local/sbin/kamailio[11061]: NOTICE: {2 450917085 BYE a9d32620-2b68-1238-048a-0cc47a18705a} acc [acc.c:279]: acc_log_request(): ACC: transaction answered: timestamp=1564270050;method=BYE;from_tag=SD5ptp899-1177933201-1564269931305;to_tag=mjKtcKaBteQ4Q;call_id=a9d32620-2b68-1238-048a-0cc47a18705a;code=404;reason=Not here;src_user=0400123123;src_domain=trunk.remote;src_ip=trunk.remote;dst_ouser=0400123123;dst_user=0400123123;dst_domain=kamailio.public-ip I’m assuming the 404 is because the Contact header I sent from Kamailio -> Trunk is rewritten, that Contact is Kamailio’s public contact IP. However the dialog has the caller contact within it referencing back to the local PBX, so I would think when Kamailio gets this dialog ID back with a BYE it would relay it back to the original contact, wouldn’t it? Thanks! Andrew