[OpenSIPS-Users] Fwd: t_check_trans and CANCEL

Bogdan-Andrei Iancu bogdan at voice-system.ro
Tue Nov 24 07:28:46 CET 2009

Hi Lasse,

RFC 3261 say very clear (it is a must) that the top most VIA in CANCEL 
must be the same as the top most VIA INVITE - it is essential for matching.

In your case it seams that the phone does a broken STUN (the INVITE has 
the public IP in VIA and the CANCEL has the private one) or you have a 
broken ALG (see if the router is SIP aware) which messes the messages.


Lasse Johnsen wrote:
> Hi,
> According to the SVN you are in and out of the file t_lookup.c mentioned below.
> I understand that the device in this case does not comply with section 9.1 of RFC3261, but could  you recommend an approach in the instance where the via in the cancel is different from the via in the invite?
> I see this behaviour both in a Cisco 7960 and an iPhone SIP softphone. This most be a common problem.
> What do you think?

Bogdan-Andrei Iancu

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