[OpenSER-Devel] [ openser-Bugs-1822692 ] 503 behavior

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Bugs item #1822692, was opened at 2007-10-30 13:07
Message generated for change (Comment added) made by bogdan_iancu
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>Category: modules
Group: ver 1.2.x
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Klaus Darilion (klaus_darilion)
>Assigned to: Bogdan (bogdan_iancu)
Summary: 503 behavior

Initial Comment:
Hi!

1. bug: Openser should change 503 to 500 when relaying responses as otherwise it will disable itself if upstream proxy is also openser with default blacklisting.

RFC 3261 page 111:

         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.

2. bug: Openser puts SIP node which sent 503 on blacklist even if Retry-After header is not present (this case should be handled like 500):

RFC 3261 page 191:

   The server is temporarily unable to process the request due to a
   temporary overloading or maintenance of the server.  The server MAY
   indicate when the client should retry the request in a Retry-After
   header field.  If no Retry-After is given, the client MUST act as if
   it had received a 500 (Server Internal Error) response.









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>Comment By: Bogdan (bogdan_iancu)
Date: 2007-11-12 18:55

Message:
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Hi Klaus,

First of all I think this discussion is valid only for the stateful
processing (TM) and not for stateless one.

Now,for 1) - the RFC makes a recomandation which makes sense (logically
speaking). Here some things need to be clarify:
   a) if there is a single branch replied with 503, then openser should
replace it with 500; Question: what reply code should be presented in
failure route? if we put 503, it will not reflect the sent reply; if you
put 500, it will not reflect the received reply
   b) if there are multiple branches, should a 503 branch be treated as it
is? should it be ignore or should it be processed as an 500? should this
branch be a potential winning branch?


For 2) - to be honest I fail to see the logic here. If a Retry-After is
present, then puting the destination in the BL only for that period of
time, make sense. But treating 503 without a RA hdr as a 500 make no sense
to be..why not use 500 directly instead of 503 without RA??

Regards,
Bogdan

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