Re: [SR-Users] Bad request when INVITE relayed to another kamailio

Hi Zhan, At first glance, it does not appear that anything about the second request is grammatically invalid. I suspect the problem you are encountering is UDP fragmentation, as explained in my blog post here: http://www.evaristesys.com/blog/sip-udp-fragmentation-and-kamailio-the-sip-… The size of the second INVITE you pasted is 1198 bytes. Add 463 bytes of encapsulated SDP body (Content-Length header), and it's 1661 bytes - over the UDP fragmentation threshold of ~1480 based on an MTU of 1500 bytes. This is due to the additional "contributions" of the second Kamailio - extra Via and Record-Route headers. Removing these extras probably puts the message length at just under the fragmentation threshold. Because the receiver does not get a fully reassembled UDP datagram, the message arrives partly formed (first UDP fragment is the only one received), the Polycom's SIP stack is confused. -- Alex On Fri, Jan 24, 2020 at 10:34:21AM -0700, Zhan Bazarov wrote: > We have Kamailio-cluster via route53(round-robin) some-domain.net > > we have two kamailio with public IP's > > phone1 is registered on kam1 > phone2 is registered on kam2 > > when we are calling from phone1 to phone2 callflow looks: > > phone1 => kam1 => asterisk => kam1 => t_relay(address of second > kamailio:5078) => kam2 => phone2 > > it works perfectly, but in case when we are using polycom as phone2 - we are > getting 404 response from polycom... > > > *Invite from second kamailio > * > 2020/01/20 10:31:21.799327 10.199.240.19:5078 -> 37.17.41.5:49811 > INVITE sip:jyu3xsfkrz6c5qn@10.3.0.116;transport=tcp SIP/2.0 > Record-Route: > <sip:10.199.240.19:5078;transport=tcp;r2=on;lr;nat=yes;rtp=bridge> > Record-Route: <sip:10.199.240.191:5078;r2=on;lr;nat=yes;rtp=bridge> > Record-Route: <sip:10.199.240.135:5078;lr> > Via: SIP/2.0/TCP > some-domain.net:5078;branch=z9hG4bK9ca3.93c2345f3eb1d4b0e1244e722a9bfb6e.0 > Via: SIP/2.0/UDP > some-domain.net:5078;rport=5078;received=10.199.240.135;branch=z9hG4bK9ca3.89b66f1dd6e86a5922180b8ed8475072.0 > Via: SIP/2.0/UDP > 10.199.240.179:7060;received=10.199.240.179;rport=7060;branch=z9hG4bKPj269365e0-798d-404b-bb77-2ad78472905c > From: "Penny" > <sip:1015@10.199.240.179>;tag=ba402508-a640-409f-ba30-dffdfe499f43 > To: <sip:jyu3xsfkrz6c5qn@10.199.240.135> > Contact: <sip:asterisk@10.199.240.179:7060;alias=10.199.240.179~7060~1> > Call-ID: c3a406ca-9ac7-423d-9697-06d0603f48d5 > CSeq: 22619 INVITE > Allow: OPTIONS, REGISTER, SUBSCRIBE, NOTIFY, PUBLISH, INVITE, ACK, BYE, > CANCEL, UPDATE, MESSAGE, REFER > Supported: timer, replaces, norefersub > Session-Expires: 1800 > Min-SE: 90 > P-Asserted-Identity: "Penny" <sip:1015@10.199.240.179> > Max-Forwards: 68 > User-Agent: Awesome Calling Platform 3.0 > Content-Type: application/sdp > Content-Length: 463 > > > *Response from POLYCOM > * > 2020/01/20 10:31:22.054766 37.17.41.5:49811 -> 10.199.240.19:5078 > SIP/2.0 400 Bad Request > Via: SIP/2.0/TCP > some-domain.net:5078;branch=z9hG4bK9ca3.93c2345f3eb1d4b0e1244e722a9bfb6e.0 > Via: SIP/2.0/UDP > some-domain.net:5078;rport=5078;received=10.199.240.135;branch=z9hG4bK9ca3.89b66f1dd6e86a5922180b8ed8475072.0 > Via: SIP/2.0/UDP > 10.199.240.179:7060;received=10.199.240.179;rport=7060;branch=z9hG4bKPj269365e0-798d-404b-bb77-2ad78472905c > From: "Penny" > <sip:1015@10.199.240.179>;tag=ba402508-a640-409f-ba30-dffdfe499f43 > To: <sip:jyu3xsfkrz6c5qn@10.199.240.135>;tag=8BC58304-83D9B045 > CSeq: 22619 INVITE > Call-ID: c3a406ca-9ac7-423d-9697-06d0603f48d5 > Record-Route: > <sip:10.199.240.19:5078;transport=tcp;r2=on;lr;nat=yes;rtp=bridge>, > <sip:10.199.240.19:5078;r2=on;lr;nat=yes;rtp=bridge>, > <sip:10.199.240.235:5078;lr> > User-Agent: PolycomVVX-VVX_450-UA/5.8.0.12848 > Accept-Language: en > Content-Length: 0 > > > > Any ideas how to fix it? > > > > -- > Sent from: http://sip-router.1086192.n5.nabble.com/Users-f3.html > > _______________________________________________ > Kamailio (SER) - Users Mailing List > sr-users(a)lists.kamailio.org > https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users