Hi, rfc 3261 (the one and only) states at section16.7
" 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 behavior is absolutely legitimate. If you want to change it you have to use the following tm parameter: http://www. kamailio.org/docs/modules/devel/modules/tm.html#remap_503_500.
Best regards,
Federico
On Mon, May 14, 2018 at 6:29 PM, Sergiu Pojoga pojogas@gmail.com wrote:
Hi Alex,
# ----- tm params ----- modparam("tm", "failure_reply_mode", 3)
I use drouting, here's the main logic.
request_route {
...
if (is_method("INVITE") && !has_totag()) { ...
# handle DR failure t_on_failure("MANAGE_DR_FAILURE"); if (!do_routing("$avp(drgroup)")) { sl_reply("503", "Unknown destination"); exit; } # Relay the request to gateway route(DR_RELAY);}
}
# DR relay route[DR_RELAY] {
if (!route(RELAY)) { sl_reply_error(); }; exit;}
# DRouting failure route failure_route[MANAGE_DR_FAILURE] {
if (t_is_canceled()) { exit; } if (t_check_status("486|600")) { xlog("L_INFO", "received BUSY, stop trying"); # --curious, 486 gets relayed fine exit; }
# try next GW if (use_next_gw()) { t_on_failure("MANAGE_DR_FAILURE"); xlog("L_INFO", "MANAGE_DR_FAILURE: Call from <$fu> withusername <$fU> going to <$ru>\n"); route(RELAY); exit;
# -- Trunk failover to PSTN number } else if (is_avp_set("$avp(s:failover)") && $avp(direction) =="in") { $ru="sip:" + $avp(s:failover) + "@someothergateway.com"; # -- basic routing, to improve by sending back to DRouting with updated $rU xlog("L_INFO", "MANAGE_DR_FAILURE: No more gateways, sending call to trunk failover destination <$ru>...\n"); route(RELAY);
} else { xlog("L_WARN", "No more routes available\n"); #t_reply ("503", "Service Unavailable"); # -- whydo we have to force a reply instead of proxy relaying whatever it is exit; } }
On Mon, May 14, 2018 at 11:34 AM, Alex Balashov <abalashov@evaristesys.com
wrote:
Hi,
- Do you have a failure_route for this transaction? If so, can you
provide it?
- Make sure the `failure_reply_mode` modparam for TM is set to 3, which
is default anyway:
https://kamailio.org/docs/modules/5.1.x/modules/tm.html#tm.p .failure_reply_mode
-- Alex
On Mon, May 14, 2018 at 11:33:15AM -0400, Sergiu Pojoga wrote:
Not sure if it's a default Kamailio behavior or something I'm doing
wrong...
When receiving a negative reply for an INVITE (more like in the 5xx
range),
proxy doesn't relay the message to the originator but instead issues
it's
own "500 Service Unavailable".
That doesn't happen, from observations so far, to "603 Declined" or "486 Busy Here" or "404 Not Found" or "200 OK" replies.
*For example, here's the negative reply proxy receives from the callee:*
2018/05/14 10:52:37.716627 65.XX.XX.166:5060 -> 65.XX.XX.167:5060 SIP/2.0 503 Service Unavailable Via: SIP/2.0/UDP 65.xx.xx.167;branch=z9hG4bK9223.00b4f3143d245a895c4bb6a107ad
d258.0;received=65.xx.xx.167;rport=5060
Via: SIP/2.0/UDP 205.xx.xx.221;received=205.xx.xx.221;rport=5060;branch=z9hG4
bKQ4XpXga0vgZ8B
From: "514XXXXXXX" <sip: 514XXXXXXX @205.xx.xx.221>;tag=tXj0NHrje9jNS To: sip:450XXXXXXX@65.xx.xx.167;tag=as18e452b7 Call-ID: 48eac296-d229-1236-a685-005056a149a4 CSeq: 122818714 INVITE Server: Asterisk Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY,
INFO,
PUBLISH, MESSAGE Supported: replaces, timer Session-Expires: 1800;refresher=uas X-Asterisk-HangupCause: Subscriber absent X-Asterisk-HangupCauseCode: 20 Content-Length: 0
*Here's what the originator gets in the final message:*
2018/05/14 10:52:37.718143 65.xx.xx.167:5060 -> 205.xx.xx.221:5060 SIP/2.0 500 Service Unavailable Via: SIP/2.0/UDP 205.xx.xx.221;rport=5060;branch=z9hG4bKQ4XpXga0vgZ8B;receive
d=205.xx.xx.221
From: "514XXXXXXX" sip:514XXXXXXX@205.xx.xx.221;tag=tXj0NHrje9jNS To: sip:450XXXXXXX@65.xx.xx.167;tag=31a2c69b5d434ef4a60796e26f
568bf0-9343
Call-ID: 48eac296-d229-1236-a685-005056a149a4 CSeq: 122818714 INVITE Server: Kamailio 5.1 Content-Length: 0
I'd like any reply to be relayed back as is, unless I do some t_check_status() => t_reply() for specific reasons (which I have none at this point).
Thanks Sergiu
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