[Kamailio-Users] DNS lookup for requests within dialog

[Klaus Darilion]

Daniel-Constantin Mierla schrieb:
> Hello,
> 
> On 24.09.2009 12:10 Uhr, catalina oancea wrote:
>> Hi,
>>
>> In my scenario kamailio is not a registrar, it's just a proxy
>> forwarding requests from asterisk to the provider.
>>   
> I see.
> 
> As Juha said, REGISTER does not create a real dialog, since the contact 
> in 200OK is the address of publisher not of destination. So a proxy does 
> not have within-dialog like routing information.
> 
> So here is a hack you can try:
> - add record route on your proxy
> - the provider should add its own record route to REGISTER reply -- if 
> it is kamailio, that is simple via append_to_reply() from textops, just 
> before save() call.

works only if the provider use Kamailio (in which case syncronized 
nonces shouldn't be a problem)

> - hope/pray that asterisk is using these dialog info for building 
> re-registration messages

I don't think that will work.

klaus


> - on your kamailio route based on Route header
> 
> 
> Cheers,
> Daniel
> 
>>
>> 2009/9/24 Daniel-Constantin Mierla <miconda at gmail.com>:
>>  
>>> Hello,
>>>
>>> On 24.09.2009 11:47 Uhr, catalina oancea wrote:
>>>    
>>>> Hi all,
>>>>
>>>>
>>>> I tested the following scenario:
>>>>
>>>> astreisk                        kamailio                
>>>> provider(hostname)
>>>>        -------------------->    dns lookup     -------------------->
>>>>          REGISTER 1                              REGISTER 1
>>>>
>>>>         <--------------------                      
>>>> <--------------------
>>>>          401                                          401
>>>>
>>>>          -------------------->   dns lookup     -------------------->
>>>>          REGISTER 2                              REGISTER 2
>>>>          (same dialog, increased cseq)
>>>>
>>>>
>>>>
>>>> It seems that kamailio does dns lookup again when receiving REGISTER
>>>> 2, although both registers are part of the same dialog. Is this the
>>>> expected behavior?
>>>>
>>>>
>>>>       
>>> IIRC now, there is no place in registrar related modules (registrar and
>>> usrloc) where DNS query is done. You have some checks in your config 
>>> that
>>> caused that.
>>>
>>> There is also an option to fetch existing contacts from location and 
>>> see if
>>> it is an update (matching by call id and cseq) and do directly
>>> save("location").
>>>
>>> Cheers,
>>> Daniel
>>>
>>> -- 
>>> Daniel-Constantin Mierla
>>> * Kamailio SIP Masterclass, Nov 9-13, 2009, Berlin
>>> * http://www.asipto.com/index.php/sip-router-masterclass/
>>>
>>>
>>>     
>>
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>>   
>