Hi Alex, RFC 3261, section "6. Choosing the best response" states:
"A proxy which receives a 503 (Service Unavailable) response SHOULD NOT forward it upstream unless it can determine that any subsequent requests it might proxy will also generate a 503. In other words, forwarding a 503 means that the proxy knows it cannot service any requests, not just the one for the Request- URI in the request which generated the 503. If the only response that was received is a 503, the proxy SHOULD generate a 500 response and forward that upstream." So Kamailio (the TM module) is doing right there. In recent versions of kamailio the TM module has a remap_503_500 parameter to control this behavior ( http://www.kamailio.org/docs/modules/devel/modules/tm.html#remap_503_500), but not in the 1.5.x branch (http://kamailio.org/docs/modules/1.5.x/tm.html ). Hope this helps...to convince your customer to upgrade ;-) Cheers, Federico On Thu, Apr 14, 2016 at 4:14 AM, Alex Balashov <abalas...@evaristesys.com> wrote: > Hi, > > I've got an installation that is still running Kamailio 1.5.x. Yes, I > know: "They're running WHAT?" As far as I'm concerned, it was EOL'd in > early 2010. Nevertheless, that doesn't stop the customer from running it. > They're probably the most change-resistant customer in the history of IP > telecom, and, knowing this industry, that's a high bar. There's not much I > can do about it. > > Anyway, I have a bit of a mystery: > > GW Proxy PBX > ================================================== > > ------- INVITE ------> > > <---- 100 Trying ---- > > -------- INVITE --------> > > <------ 100 Trying ------ > > <- 503 Service Unavailable > > ---------- ACK ---------> > > <- 500 Service Una... > > -------- ACK --------> > > > There is no basis in the configuration for the translation of the "503 > Service Unavailable" reply to "500 Service Unavailable", so I'm thinking it > has to be rooted in some default module behaviour. > > Any insight would be appreciated! > > -- Alex > > -- > Alex Balashov | Principal | Evariste Systems LLC > 1447 Peachtree Street NE, Suite 700 > Atlanta, GA 30309 > United States > > Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct) > Web: http://www.evaristesys.com/, http://www.csrpswitch.com/ > > _______________________________________________ > SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list > sr-users@lists.sip-router.org > http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users >
_______________________________________________ SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users@lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
