[Kamailio-Users] What is wrong with this NOTIFY packet

[Olle E. Johansson]

15 feb 2010 kl. 10.01 skrev Alex Balashov:

> On 02/15/2010 03:58 AM, Alex Hermann wrote:
>> On Monday 15 February 2010 09:25:41 Asterisk User wrote:
>>> Now to implement MWI i send NOTIFY packet from Asterisk to Kamailio and
>>>  from kamailio to SIP extension (Grandstream GXP2000).
>>> here is the packet that travels from kamailio to extension and the response
>>> sent from extension to kamilio.
>>> ===========================
>>> NOTIFY sip:1111111 at arzoo.com<sip%3A1111111 at arzoo.com>  SIP/2.0
>>> Max-Forwards: 10
>>> Record-Route:<sip:172.18.100.74;lr;nat=yes>
>>> Via: SIP/2.0/UDP 172.18.100.74;branch=z9hG4bK3c3.e1003f03.0
>>> Via: SIP/2.0/UDP 127.0.0.1:45382
>>> ;received=172.18.100.73;branch=z9hG4bK.4f83530d;rport=45382;alias
>>> Via: SIP/2.0/UDP 172.18.100.73:5060
>>> From:<sip:111 at arzoo.com<sip%3A111 at arzoo.com>>
>>> To:<sip:1111111 at arzoo.com<sip%3A1111111 at arzoo.com>>
>> 
>> NOTIFY's are in-dialog requests. Your From and To header are missing the
>> required tags (and look a bit suspicious by themselves too because of the
>> double<>). The grandstream probably can't match the NOTIFY to the correct
>> subscription and follows a code path that for some reason decides to answer
>> 415 instead of a 481.
> 
> Good eye!  That too.
> 
> Basically, Granstream sucks.  Don't bother.

Well, I think that Asterisk has a bit of blame to take here too. Asterisk sends NOTIFY without having received a SUBSCRIBE, which is why they look out-of-dialog. You can configure Asterisk to only send NOTIFY with a subscription, in which case this won't happen. It's an old story, and most phones actually accept NOTIFY's for voicemail out-of-the-blue, outside of any known dialogs.

/O