[Freeswitch-users] Alcatel 4018 - "481 Call Does Not Exist" on re-REGISTER

[Christian Benke]

On 16 March 2011 16:18, M. Ranganathan <mranga at gmail.com> wrote:
> Change the cseq number (increment by 1) when you re-register. See if that
> fixes it.

The phone is in fact incrementing the CSeq already, so no,
unfortunately this does not help(And i actually would not have any
option to change it if it didn't).

So this is what i found in the RFCs:

http://www.ietf.org/rfc/rfc3261.txt 22.4.8. references RFC 2617(HTTP
Authentication: Basic and Digest Access Authentication)
http://www.ietf.org/rfc/rfc2617.txt 3.2.1 says:

     An implementation might choose not to accept a previously used
     nonce or a previously used digest, in order to protect against a
     replay attack. Or, an implementation might choose to use one-time
     nonces or digests for POST or PUT requests and a time-stamp for GET
     requests.

and

  4.3 Limited Use Nonce Values

   The Digest scheme uses a server-specified nonce to seed the
   generation of the request-digest value (as specified in section
   3.2.2.1 above).  As shown in the example nonce in section 3.2.1, the
   server is free to construct the nonce such that it may only be used
   from a particular client, for a particular resource, for a limited
   period of time or number of uses, or any other restrictions.  Doing
   so strengthens the protection provided against, for example, replay
   attacks (see 4.5).

This makes a lot of sense of course, so i have plenty arguments now to
ditch this phone(Alcatel 4018) as it is not behaving correctly(Unless
i find a newer firmware).

Regards,
Christian