[Kamailio-Users] DNS lookup for requests within dialog

Daniel-Constantin Mierla miconda at gmail.com
Thu Sep 24 13:45:02 CEST 2009


Hello,

On 24.09.2009 13:22 Uhr, catalina oancea wrote:
> Hi again
>
>
> I probably misunderstood the RFC.

I misunderstood your first email, I though is about registration 
refreshes (send updates to same server). Not the authentication case, 
because there is no dialog created in this situation, not even for 
INVITE. Dialog is created only after a 200ok (early dialogs after >100 < 
200 replies).

htable is indeed an option.

Cheers,
Daniel

>  But an INVITE does create a dialog,
> and the situation:
>
> asterisk                        kamailio                provider(hostname)
>          -------------------->    dns lookup     -------------------->
>          INVITE 1                                 INVITE 1
>
>         <--------------------                      <--------------------
>          407                                          407
>
>          -------------------->   dns lookup     -------------------->
>         INVITE 2                                 INVITE 2
>          (authenticated)
>
>
> would have the same problem.
>
> But the htable idea seems OK, I will try it.
>
>
> Thanks everybody
>
>
>
>
> 2009/9/24 Klaus Darilion <klaus.mailinglists at pernau.at>:
>   
>> 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/
>>>>>
>>>>>
>>>>>
>>>>>           
>>>> _______________________________________________
>>>> Kamailio (OpenSER) - Users mailing list
>>>> Users at lists.kamailio.org
>>>> http://lists.kamailio.org/cgi-bin/mailman/listinfo/users
>>>> http://lists.openser-project.org/cgi-bin/mailman/listinfo/users
>>>>
>>>>
>>>>         
>
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>
>   

-- 
Daniel-Constantin Mierla
* Kamailio SIP Masterclass, Nov 9-13, 2009, Berlin
* http://www.asipto.com/index.php/sip-router-masterclass/




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