[OpenSIPS-Users] Need ideas to tamper with CSeq

[Anca Vamanu]

On 03/31/2011 03:21 AM, Cindy Leung wrote:
> I know I'm doing something bad here.  However, we are having a problem with one of the SIP phones that we support.  When it sends out an INVITE and then CANCEL, the CANCEL is not being forwarded.  We are suspecting that it is caused by a wrong CSeq value.
>
> INVITE #1 gets challenged.
> INVITE #2 accepted.
> CANCEL is sent, but CSeq is the same as the one in INVITE #1.
>
It is ok (RFC compliant) for the Cseq in CANCEL to be the same as the 
Cseq in INVITE:
RFC 3261 - section 9.1:

  "The Request-URI, Call-ID, To, the numeric part of CSeq, and From header
    fields in the CANCEL request MUST be identical to those in the
    request being cancelled, including tags. "

Regards,

-- 
Anca Vamanu
OpenSIPS Developer



> It is less than ideal for us to contact their support and we'd like to get it fixed asap.  I've tried subst(), remove_hf and append_hf to play with CSeq with no luck.
>
> Any suggestions?  Thanks!
>
>
> Cinthi