[asterisk-users] Invite + decreasing sequence number => 500 Error?

[Matthew Jordan]

It's not a bug - decrementing the CSeq header field value is directly in
violation of RFC 3261.  From section 22.2:

   When a UAC resubmits a request with its credentials after receiving a
   401 (Unauthorized) or 407 (Proxy Authentication Required) response,
   it MUST increment the CSeq header field value as it would normally
   when sending an updated request.

Matthew Jordan
Digium, Inc. | Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: http://digium.com & http://asterisk.org

----- Original Message -----
> From: "Benoit Panizzon" <benoit.panizzon at imp.ch>
> To: asterisk-users at lists.digium.com
> Sent: Monday, April 16, 2012 7:12:09 AM
> Subject: [asterisk-users] Invite + decreasing sequence number => 500 Error?
> 
> Hi out there
> 
> We have a strange Problem here with invites.
> 
> We observe this SIP conversation.
> 
> C3 PBX <-> Asterisk
> 
> Case 1. Sequence Numer always increasing:
> 
> => Invite
> <= 401 Unauthenticated
> => Invite+auth with sequence number > previous Invite.
> <= 100 Trying etc. Works OK.
> 
> Case 2. Sequence Number decreasing.
> 
> => Invite
> <= 401 Unauthenticated
> => Invite+auth with sequence number < previous Invite.
> <= 500 ERROR
> 
> I was browsing the SIP rfc and I cannot find any clue if in this case
> the
> sequence numbers must be increasing (the C3 PBX is wrong) or if I
> have sumbled
> over an asterisk bug.
> 
> Is there anyone who knows?
> 
> Benoit Panizzon
> --
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