Many, many thanks ! I've posted the full dialog unredacted here: https://pastebin.com/EE9iwgZf
The OK from Kamailio back to VOIP provider has Record-Route: <sip:KAMAILIOIP;lr=on;ftag=SD2rbta01-8dd0e72b-0016-0379- 0000-0000;did=e0c.e0a1> Contact: <sip:NUMBER@ASTERISKIP:5060> So my understanding is that the ACK should be ACK sip:NUMBER@ASTERISKIP:5060 SIP/2.0 .... and not ACK sip:NUMBER@KAMAILIOIP:5060 SIP/2.0 Am I understanding correctly ? Rgds J On Mon, Jan 8, 2018 at 11:28 AM, Sebastian Damm <[email protected]> wrote: > Hi, > > On Mon, Jan 8, 2018 at 2:39 PM, Jean Cérien <[email protected]> wrote: > >> >> Thanks for this answer. The voip provider is not really eager to alter >> its SBC as it considers that the contact field is not mandatory in the ACK. >> The RFC states (section 8.1.1.8) >> > > The problem is not that the ACK doesn't carry a Contact header. The > problem is that the ACK is constructed incorrectly. This is what the RfC > says to UAC behavior (section 12.1.2): > > The route set MUST be set to the list of URIs in the Record-Route header > field from the response, taken in reverse order and preserving all URI > parameters. If no Record-Route header field is present in the response, the > route set MUST be set to the empty set. This route set, even if empty, > overrides any pre-existing route set for future requests in this dialog. *The > remote target MUST be set to the URI from the Contact header field of the > response.* > > This is what the carrier's SBC gets wrong. It doesn't address your > Asterisk but instead addresses your Kamailio, although the Contact of your > 200 OK (hopefully) contains the Asterisk IP. > > Please verify that your 200 OK going to the carrier actually does carry a > Contact header with the Asterisk IP, but if it does, section 12.1.2 of the > SIP RfC could help when arguing with the carrier. > > Regards > Sebastian > > _______________________________________________ > Kamailio (SER) - Users Mailing List > [email protected] > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users > >
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