[OpenSIPS-Users] Wrong socket selected by proxy when forwarding requests

Jan Blom jan.blom at peopleinteractive.se
Fri Aug 19 19:42:01 CEST 2011

Hi Bogdan,


Best regards,

-----Original Message-----
From: Bogdan-Andrei Iancu [mailto:bogdan at opensips.org] 
Sent: den 19 augusti 2011 17:20
To: OpenSIPS users mailling list
Cc: Jan Blom
Subject: Re: [OpenSIPS-Users] Wrong socket selected by proxy when forwarding requests

Hi Jam,

So, what you say is that the A sends ACK on 5002 to opensips and opensips sends it to B via 5060 port ?


On 08/15/2011 03:56 PM, Jan Blom wrote:
> Hello,
> I have noticed a problem when using mhomed=1. The problem was discovered in 1.6.3, but has also been verified in 1.7.0-beta.
> I have Opensips (only) listening on two ports on the same IP address. Obviously this doesn't require mhomed=1, but that was a leftover from an older setup. And I wasn't expecting it to cause trouble anyway.
> This is a snippet from the opensips.cfg:
> 	auto_aliases=no
> 	mhomed=1
> 	listen=udp:178.16.xxx.xxx:5060
> 	listen=udp:178.16.xxx.xxx:5002
> I have two user agents that register with the proxy, both using port 5002. In the socket field from the subscriber table, I can verify that both are correctly associated with port 5002 (having value udp:178.16.xxx.xxx:5002).
> User agent A then calls user agent B, again by sending the INVITE to port 5002. The INVITE request is properly forwarded to user agent B, using src port 5002.
> However, the ACK request sent when B answers and the BYE request when B hangs up will both, incorrectly, be forwarded by the proxy using src port 5060. The wrong socket is selected by the proxy.
> This will then prevent proper call setup and termination if any NAT is present.
> If I remove the mhomed=1 setting, the problem will disappear.
> So this is currently not a problem for me since the workaround exists. However, it might be a problem for others as well, where you potentially do need a multi-homed setup.
> Best regards,
> Jan Blom
> People Interactive
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> Users at lists.opensips.org
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Bogdan-Andrei Iancu
OpenSIPS eBootcamp - 19th of September 2011 OpenSIPS solutions and "know-how"

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