[Users] 473 Filtered destination?

Bogdan-Andrei Iancu bogdan at voice-system.ro
Fri Mar 30 16:12:06 CEST 2007


Hi Stefan,

Stefan Prelle wrote:
> Hi all,
>
> Am Donnerstag, den 29.03.2007, 09:17 -0400 schrieb Ovidiu Sas:
>   
>> You can disable the dns blacklist feature in openser.cfg:
>> disable_dns_blacklist=true
>>     
>
> I ran into the same problem when trying to upgrade to 1.2.
> Our PSTN-Gateway regulary maps some SS7 reason codes to a SIP 503.
> >From what I understand from
> http://www.openser.org/docs/modules/1.2.x/tm.html#AEN103 , the first 503
> received, blacklists the originating IP address (our gateway). 
> So, a few seconds after starting the 1.2 version, the OpenSER blocked
> the whole trunk (running several thousand calls), just because one call
> produced an 503, which originated in the PSTN.
>   

unfortunately we have again an example of differences between theory and 
practice. The RFC 3263, section 4.3 says:

   For SIP requests, failure occurs if the transaction layer reports a
   503 error response or a transport failure of some sort.......


also RFC 3261 says:

1.5.4 503 Service Unavailable

   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.

   A client (proxy or UAC) receiving a 503 (Service Unavailable) SHOULD
   attempt to forward the request to an alternate server.  It SHOULD NOT
   forward any other requests to that server for the duration specified
   in the Retry-After header field, if present.

   Servers MAY refuse the connection or drop the request instead of
   responding with 503 (Service Unavailable).


so, my impression is that the GW does not follow the RFC specs when come 
to error codes.
> I think the blacklisting feature shouldn't be enabled by default or at
> least should the release notes carry a huge red blinking warning that
> this auto blocking might be harmful.
>   
yes, we need to work out this for the future.

Regards,
Bogdan
> Regards,
>   Stefan
>
>
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>   





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