Hi all

Experiencing a commonly reported issue where calls drop out after 30 seconds or so. Mainly because the provider hangs up after not recognising/receiving ACK in response to 200 OK.

Unfortunately (or maybe fortunately), I haven't had much experience with Enswitch so was hoping someone in the community might help guide me as to which rules Enswitch might be using to match ACKs to calls in progress. Maybe there is another avenue I should be investigating.


Here's a sample of the 200 OK and ACK that repeats.

13:44:04.155646 IP PROVIDERIP.5060 > 172.21.0.226.5060: SIP, length: 1058
E..>.M..?..Ug.v..........*J.SIP/2.0 200 OK^M
Via: SIP/2.0/UDP 172.21.0.226;rport=5060;branch=z9hG4bKfe94.efbf7fbcaf8bd15243a61fdc9d6d1e78.0^M
Via: SIP/2.0/UDP 127.0.0.1:5080;branch=z9hG4bK65f00a0c;rport=5080^M
Record-Route: <sip:PROVIDERIP;lr=on>^M
Record-Route: <sip:172.21.0.226;r2=on;lr=on;ftag=as65919d92;nat=yes>^M
Record-Route: <sip:127.0.0.1;r2=on;lr=on;ftag=as65919d92;nat=yes>^M
From: "asterisk" <sip:PROVIDERUSER@PROVIDERIP:5080>;tag=as65919d92^M
To: <sip:PHONENUMBER@PROVIDERIP>;tag=as260fefaa^M
Call-ID: 271ac7a174d613cd0b94504353733a2c@PROVIDERIP^M
CSeq: 103 INVITE^M
Server: Enswitch^M
Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY, INFO, PUBLISH^M
Supported: replaces^M
Contact: <sip:PHONENUMBER@PROVIDERMEDIAIP:5060>^M
Content-Type: application/sdp^M
Content-Length: 286^M
^M
v=0^M
o=root 2110894460 2110894461 IN IP4 PROVIDERMEDIAIP^M
s=Asterisk PBX 11.3.0^M
c=IN IP4 PROVIDERMEDIAIP^M
t=0 0^M
m=audio 15594 RTP/AVP 0 8 3 101^M
a=rtpmap:0 PCMU/8000^M
a=rtpmap:8 PCMA/8000^M
a=rtpmap:3 GSM/8000^M
a=rtpmap:101 telephone-event/8000^M
a=fmtp:101 0-16^M
a=ptime:20^M
a=sendrecv^M

13:44:04.164519 IP 172.21.0.226.5060 > PROVIDERIP.5060: SIP, length: 525
E..)!A..@..v....g.v.......T.ACK sip:PHONENUMBER@PROVIDERIP:5060 SIP/2.0^M
Via: SIP/2.0/UDP 172.21.0.226;branch=z9hG4bKfe94.472e9fc0479de79b4f176cc9585d8880.0^M
Via: SIP/2.0/UDP 127.0.0.1:5080;branch=z9hG4bK752b5264;rport=5080^M
Route: <sip:PROVIDERIP;lr=on>^M
Max-Forwards: 69^M
From: "asterisk" <sip:PROVIDERUSER@PROVIDERIP:5080>;tag=as65919d92^M
To: <sip:PHONENUMBER@PROVIDERIP>;tag=as260fefaa^M
Contact: <sip:PROVIDERUSER@127.0.0.1:5080>^M
Call-ID: 271ac7a174d613cd0b94504353733a2c@PROVIDERIP^M
CSeq: 103 ACK^M
User-Agent: Elastix 3.0^M
Content-Length: 0^M