[asterisk-users] Securing Asterisk - How to avoid sending, "SIP/2.0 603 Declined"

[Paul Belanger]

On 11-07-23 12:34 AM, Bruce B wrote:
> Robert thanks for weighing in.
>
> So, you are saying that FreeSwitch on it's own can tackle issues like this
> without the need of OpenSIPs? Can you elaborate please?
>
If true, I'd be curious to see how they accomplish it.  I've never tried 
FreeSwitch but as more and more people mention it I should take some 
time to play with it.

However, from a SIP point of view, not replying to an INVITE message is 
not an option according to the SIP RFC[1]

13.3.1.3 The INVITE is Rejected

    A common scenario occurs when the callee is currently not willing or
    able to take additional calls at this end system.  A 486 (Busy Here)
    SHOULD be returned in such a scenario.  If the UAS knows that no
    other end system will be able to accept this call, a 600 (Busy
    Everywhere) response SHOULD be sent instead.  However, it is unlikely
    that a UAS will be able to know this in general, and thus this
    response will not usually be used.  The response is passed to the
    INVITE server transaction, which will deal with its retransmissions.

    A UAS rejecting an offer contained in an INVITE SHOULD return a 488
    (Not Acceptable Here) response.  Such a response SHOULD include a
    Warning header field value explaining why the offer was rejected.

[1] http://www.ietf.org/rfc/rfc3261.txt

-- 
Paul Belanger
Digium, Inc. | Software Developer
twitter: pabelanger | IRC: pabelanger (Freenode)
Check us out at: http://digium.com & http://asterisk.org