Hey List, I digged in further. Following two ACKs are working: Working ACK from RegA for CANCEL of RegB: ACK sip:7vcakkpv@192.0.2.136;transport=ws SIP/2.0 Via: SIP/2.0/WSS 10.250.5.74:8083;branch=z9hG4bK000c.446f4cee5bd63591fa35ea12e1a1e393.0 Max-Forwards: 68 To: <sip:dnagorny@r5dev-kam1.robot5.de>;tag=31c6c3ijb5 From: "Testaccount" <sip:4@r5dev-kam1.robot5.de>;tag=p0tp4c68v2 Call-ID: 145jsg3213nfja1q0t5i CSeq: 9367 ACK Content-Length: 0 Working ACK from RegA on 200OK from Outside call: ACK sip:192.168.1.30 SIP/2.0 Route: <sip:Tr3Hu/WYcOQZLAYK+gVKH5MK+gUR2JQ=@10.250.5.74:8083;transport=ws;r2=on;lr=on;ftag=er9qb49if5> Route: <sip:Tr3Hu/WYcOQZLAYK+gVKH5MK+gUR2JQ=@192.168.1.150;r2=on;lr=on;ftag=er9qb49if5> Via: SIP/2.0/WSS 192.0.2.136;branch=z9hG4bK6855215 Max-Forwards: 69 To: <sip:185511@r5dev-kam1.robot5.de>;tag=02d4bbc728087a7b7e530be0ae5896ca From: "Dimitry Nagorny" <sip:dnagorny@r5dev-kam1.robot5.de>;tag=er9qb49if5 Call-ID: 38q2he9qrral8daksm52 CSeq: 3036 ACK Allow: INVITE,ACK,CANCEL,BYE,UPDATE,MESSAGE,OPTIONS,REFER,INFO Supported: outbound User-Agent: JsSIP 1.0.1 Content-Length: 0 So I am completely lost why this one is still not working: Non-Working ACK from RegA on 200OK from RegB: ACK sip:t55khn2h@192.0.2.233;alias=10.250.5.17~55445~6;transport=ws SIP/2.0 Route: <sip:Tr3Hu/WYcOQZLAYK+gVKH5MK+gUR2JQ=@10.250.5.74:8083;transport=ws;lr=on;ftag=7q6slak74s> Via: SIP/2.0/WSS 192.0.2.136;branch=z9hG4bK5235121 Max-Forwards: 69 To: <sip:4@r5dev-kam1.robot5.de>;tag=e5ilujm0o4 From: "Dimitry Nagorny" <sip:dnagorny@r5dev-kam1.robot5.de>;tag=7q6slak74s Call-ID: 38q2hqlkh16hmu8157vn CSeq: 4244 ACK Allow: INVITE,ACK,CANCEL,BYE,UPDATE,MESSAGE,OPTIONS,REFER,INFO Supported: outbound User-Agent: JsSIP 1.0.1 Content-Length: 0 Kamailio still throws the errors mentioned below. This is my ACK Route: route[WITHINDLG] { if (!has_totag()) { return; } ... if (is_method("ACK")) { if (t_check_trans()) { route(RELAY); exit; } else { exit; } } ... } Open for any suggestions... Best Regards Dimitry Nagorny Trainee Von: sr-users [mailto:sr-users-bounces@lists.sip-router.org] Im Auftrag von Nagorny, Dimitry Gesendet: Donnerstag, 16. Juni 2016 09:47 An: Kamailio (SER) - Users Mailing List &lt;sr-users(a)lists.sip-router.org&gt; Betreff: [SR-Users] ACK not sent out Hello List, I have a setup of two WebRTC-Clients registered to kamailio. RegA calls RegB. Signalling itself for connection seems to work until the point RegA receives the 200Ok and wants to send the ACK, kamailio throws errors. Here are the 200Ok with the following ACK and the errors that kamailio writes: 200OK (from RegB to RegA, successful): SIP/2.0 200 OK Record-Route: <sip:zfHrSW4KTMuuxQYK+gVKH5MK+gUR1jc=@10.250.5.74:8083;transport=ws;lr=on;ftag=3bege11omg> Via: SIP/2.0/WSS 192.0.2.1;rport=54839;received=10.250.5.17;branch=z9hG4bK415866 To: <sip:dnagorny@r5dev-kam1.robot5.de>;tag=ecmmlvc4ee From: "Testaccount" <sip:4@r5dev-kam1.robot5.de>;tag=3bege11omg Call-ID: vu8rkkgki2uupuf2cqf4 CSeq: 2017 INVITE Contact: <sip:l1jevtog@192.0.2.59;alias=10.250.5.17~54838~6;alias=10.250.5.17~54838~6;transport=ws> Supported: ice,replaces,outbound Content-Type: application/sdp Content-Length: 1001 v=0 o=mozilla...THIS_IS_SDPARTA-47.0 4652302965311172452 0 IN IP4 0.0.0.0 s=- t=0 0 a=sendrecv a=fingerprint:sha-256 1A:88:2D:6E:9F:82:14:E0:A2:DB:A7:16:56:00:2C:25:1B:D2:D1:EE:B2:D5:ED:6F:E1:7C:5C:B4:1A:30:9C:85 a=group:BUNDLE audio a=ice-options:trickle a=msid-semantic:WMS * m=audio 30710 UDP/TLS/RTP/SAVPF 111 c=IN IP4 10.250.5.74 a=candidate:0 1 UDP 2122252543 10.250.5.17 52581 typ host a=candidate:1 1 UDP 1686052863 87.158.246.174 49807 typ srflx raddr 10.250.5.17 rport 52581 a=end-of-candidates a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level a=fmtp:111 maxplaybackrate=48000;stereo=1 a=ice-pwd:4d722747e7d3b3caa360ebe9e646fb44 a=ice-ufrag:2b7e23b8 a=mid:audio a=msid:{5cea7c38-cc3e-4bd2-9a3b-5d2381f0acf9} {0236e1cf-dfdc-4c94-8ce0-59f52a23ebb1} a=rtpmap:111 opus/48000/2 a=setup:active a=ssrc:565594393 cname:{7df4b0da-093c-4c2d-b154-0b860b43f575} a=sendrecv a=rtcp:30710 a=rtcp-mux a=candidate:Y2XhN5oQNoH6nRph 1 UDP 2122252799 10.250.5.74 30710 typ host ACK (from RegA to RegB, unsuccessfull): ACK sip:l1jevtog@192.0.2.59;alias=10.250.5.17~54838~6;transport=ws SIP/2.0 Route: <sip:zfHrSW4KTMuuxQYK+gVKH5MK+gUR1jc=@10.250.5.74:8083;transport=ws;lr=on;ftag=3bege11omg> Via: SIP/2.0/WSS 192.0.2.1;branch=z9hG4bK2821443 Max-Forwards: 69 To: <sip:dnagorny@r5dev-kam1.robot5.de>;tag=ecmmlvc4ee From: "Testaccount" <sip:4@r5dev-kam1.robot5.de>;tag=3bege11omg Call-ID: vu8rkkgki2uupuf2cqf4 CSeq: 2017 ACK Allow: INVITE,ACK,CANCEL,BYE,UPDATE,MESSAGE,OPTIONS,REFER,INFO Supported: outbound User-Agent: JsSIP 1.0.1 Content-Length: 0 Thrown Errors: kamailio[5009]: INFO: <script>: Is natted kamailio[5009]: INFO: <script>: From: sip:4@r5dev-kam1.robot5.de To: sip:l1jevtog@192.0.2.59;alias=10.250.5.17~54838~6;transport=ws @ <null> Via: SIP/2.0/WSS 192.0.2.1;branch=z9hG4bK4386608 Route: <null> vu8rkkgki2uupuf2cqf4 kamailio[5009]: ERROR: <core> [forward.c:529]: forward_request(): cannot forward to af 2, proto 5 no corresponding listening socket kamailio[5009]: ERROR: sl [sl_funcs.c:363]: sl_reply_error(): ERROR: sl_reply_error used: I'm terribly sorry, server error occurred (7/SL) I don't understand these errors. Can anybody explain and point me what needs to be fixed? Using Kamailio 4.3.5 on CentOS7.2, funny info if I call from outside(PSTN/FreeSWITCH) to kamailio into WebRTC-Client it works w/o problems. Respectfully Dimitry Nagorny Trainee