[SR-Users] How Kamailio processes SIP ACK on local 4XX reply?

Hello! I have some misunderstanding regarding the processing of SIP ACK on local Kamailio 4xx reply (eg 407 Proxy Authentication Required). In the picture below you can see that such a message just goes through the proxy and moreover gets into the *request_route* section. I expect this SIP ACK to be consumed by the sl module without hitting script logic. [image: image.png] I put the part below to the very top of the *request_route* section: *request_route* { if ( is_method("ACK") ) { t_check_trans(); $var(error) = $rc; xlog("L_ERR", "[CATCH_ACK] m=$rm cseq=$cs ru=$ru err=$var(error) [$ci]"); } .... And as a result, I detected in syslog: May 7 16:15:34 test-edge /usr/sbin/kamailio[11642]: ERROR: <script>: [CATCH_ACK] m=ACK cseq=153 ru=sip:mod_sofia@10.0.7.3:5060 err=-1 [051e7c50-0b10-1239-2996-001dd8b71cb2] *SIP re-INVITE (hold) from Phone:* 2020/05/07 16:15:34.629973 176.6.4.6:1024 -> 185.9.7.7:5060 INVITE sip:mod_sofia@10.0.7.3:5060 SIP/2.0 Via: SIP/2.0/UDP 192.168.11.111:5060 ;branch=z9hG4bK00475de2da8eea118ec67caaaddc98fb;rport Route: <sip:185.9.7.7;r2=on;lr=on;did=f98.f3f4> Route: <sip:10.0.7.5;r2=on;lr=on;did=f98.f3f4> Route: <sip:10.0.7.6;lr=on;did=f98.fbe> From: <sip:312222222222@10.0.7.6>;tag=00dfd3d8da8eea118ec67caaaddc98fb To: "Denys VOIP" <sip:5008@185.9.7.7>;tag=54Q0XNHgXBUvp Call-ID: 051e7c50-0b10-1239-2996-001dd8b71cb2 CSeq: 153 INVITE Contact: <sip:312222222222@192.168.11.111:5060 ;gr=00DCB21F-BD8E-EA11-8E88-7CAAADDC98FB> Content-Type: application/sdp Allow: INVITE, ACK, BYE, CANCEL, INFO, MESSAGE, NOTIFY, OPTIONS, REFER, UPDATE, PRACK Max-Forwards: 70 Supported: 100rel, replaces, from-change, gruu User-Agent: SIPPER for PhonerLite Content-Length: 313 v=0 o=- 3858283927 2 IN IP4 192.168.11.111 s=SIPPER for PhonerLite c=IN IP4 192.168.11.111 t=0 0 m=audio 5062 RTP/AVP 8 0 9 107 101 a=rtpmap:8 PCMA/8000 a=rtpmap:0 PCMU/8000 a=rtpmap:9 G722/8000 a=rtpmap:107 opus/48000/2 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ssrc:782125221 a=sendonly *SIP 407 from Kamailio:* 2020/05/07 16:15:34.632298 185.9.7.7:5060 -> 176.6.4.6:1024 SIP/2.0 407 Proxy Authentication Required Via: SIP/2.0/UDP 192.168.11.111:5060 ;branch=z9hG4bK00475de2da8eea118ec67caaaddc98fb;rport=1024;received=176.6.4.6 From: <sip:312222222222@10.0.7.6>;tag=00dfd3d8da8eea118ec67caaaddc98fb To: "Denys VOIP" <sip:5008@185.9.7.7>;tag=54Q0XNHgXBUvp Call-ID: 051e7c50-0b10-1239-2996-001dd8b71cb2 CSeq: 153 INVITE Proxy-Authenticate: Digest realm="185.9.7.7", nonce="XrQaXjfjyrftyrtiyrft7uO" Server: kamailio (5.2.2 (x86_64/linux)) Content-Length: 0 *SIP ACK from Phone:* 2020/05/07 16:15:34.672872 176.6.4.6:1024 -> 185.9.7.7:5060 ACK sip:mod_sofia@10.0.7.3:5060 SIP/2.0 Via: SIP/2.0/UDP 192.168.11.111:5060 ;branch=z9hG4bK00475de2da8eea118ec67caaaddc98fb;rport Route: <sip:185.9.7.7;r2=on;lr=on;did=f98.f3f4> Route: <sip:10.0.7.5;r2=on;lr=on;did=f98.f3f4> Route: <sip:10.0.7.6;lr=on;did=f98.fbe> From: <sip:312222222222@10.0.7.6>;tag=00dfd3d8da8eea118ec67caaaddc98fb To: "Denys VOIP" <sip:5008@185.9.7.7>;tag=54Q0XNHgXBUvp Call-ID: 051e7c50-0b10-1239-2996-001dd8b71cb2 CSeq: 153 ACK Content-Length: 0 *SIP ACK (unwanted) from Kamailio to Core:* 2020/05/07 16:15:34.675546 10.0.7.5:5060 -> 10.0.7.6:5060 ACK sip:mod_sofia@10.0.7.3:5060 SIP/2.0 Max-Forwards: 10 Via: SIP/2.0/UDP 10.0.7.5;branch=z9hG4bK0d46.c33c3556c3cffbac49e717352b3575f6.0 Via: SIP/2.0/UDP 192.168.11.111:5060 ;received=176.6.4.6;branch=z9hG4bK00475de2da8eea118ec67caaaddc98fb;rport=1024 Route: <sip:10.0.7.6;lr=on;did=f98.fbe> From: <sip:312222222222@10.0.7.6>;tag=00dfd3d8da8eea118ec67caaaddc98fb To: "Denys VOIP" <sip:5008@185.9.7.7>;tag=54Q0XNHgXBUvp Call-ID: 051e7c50-0b10-1239-2996-001dd8b71cb2 CSeq: 153 ACK Content-Length: 0 loose-route: done *IP addresses and call-flow:* Core (10.0.7.6) --> [ Kamailio (10.0.7.5) -> Kamailio (185.9.7.7) ] --> Phone (176.6.4.6) [root@test-edge kamailio]$ kamailio -v version: kamailio 5.2.2 (x86_64/linux) flags: STATS: Off, USE_TCP, USE_TLS, USE_SCTP, TLS_HOOKS, USE_RAW_SOCKS, DISABLE_NAGLE, USE_MCAST, DNS_IP_HACK, SHM_MEM, SHM_MMAP, PKG_MALLOC, Q_MALLOC, F_MALLOC, TLSF_MALLOC, DBG_SR_MEMORY, USE_FUTEX, FAST_LOCK-ADAPTIVE_WAIT, USE_DNS_CACHE, USE_DNS_FAILOVER, USE_NAPTR, USE_DST_BLACKLIST, HAVE_RESOLV_RES ADAPTIVE_WAIT_LOOPS=1024, MAX_RECV_BUFFER_SIZE 262144 MAX_URI_SIZE 1024, BUF_SIZE 65535, DEFAULT PKG_SIZE 8MB poll method support: poll, epoll_lt, epoll_et, sigio_rt, select. id: unknown compiled on 19:29:40 Jun 20 2019 with gcc 4.8.5 -- BR, Denys Pozniak