[SR-Users] How to detect NAT during authenticated registration of clients which adjust the headers

[Awal Junanto]

Because I may need to bridge media when another client who may not handle
NAT that well calls this client.

On Fri, 28 Feb 2020 at 18:05, Yuriy Gorlichenko <ovoshlook at gmail.com> wrote:

> But why it becomes a problem? It looks like client reloves NAT issue on
> his side. So during the call of this user you will send request to the
> proper destination address anyway.
>
> On Fri, 28 Feb 2020, 18:03 David Villasmil, <
> david.villasmil.work at gmail.com> wrote:
>
>> Can you paste the challenge and responses?
>>
>> On Fri, 28 Feb 2020 at 14:50, Awal Junanto <a.junanto at gmail.com> wrote:
>>
>>> I added a call to add_uri_param("nat=yes") before auth_challenge("$fd",
>>> "0"), but couldn't see any difference in the actual SIP messages. The
>>> challenge (and the response) didn't contain that newly added keyword. Or am
>>> I missing something here?
>>>
>>> On Fri, 28 Feb 2020 at 13:58, David Villasmil <
>>> david.villasmil.work at gmail.com> wrote:
>>>
>>>> There probably is a better way of doing this, but maybe you can store
>>>> the fact that the first register came from a natted device in the locations
>>>> table (or a hash).
>>>>
>>>> Or maybe add a parameter when challenging where you state the client is
>>>> natting?
>>>>
>>>> Something like this
>>>>
>>>>
>>>> https://kamailio.org/docs/modules/3.1.x/modules_k/siputils.html#id2769802
>>>>
>>>>
>>>> Hope that helps
>>>>
>>>> David
>>>>
>>>> On Fri, 28 Feb 2020 at 12:03, Awal Junanto <a.junanto at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> We are building a service where we need to detect NAT when the clients
>>>>> register to our server. We are struggling in analyzing NAT status of some
>>>>> clients which modify their IP addresses/ports in the headers according to
>>>>> the value of "received" parameter sent during "401 Unauthorized" response.
>>>>>
>>>>> Here's the flow:
>>>>>
>>>>> Client->Server
>>>>> REGISTER sip:...
>>>>> Via: SIP/2.0/TLS 192.168.0.1:41157
>>>>> ;rport;branch=z9hG4bKPj30093e5d-550d-4d4c-a9a2-22c3bd1cda7e;alias
>>>>> Contact: <sip:user at 192.168.0.1:42251;transport=TLS;ob>
>>>>> ...
>>>>> Server->Client
>>>>> SIP/2.0 401 Unauthorized
>>>>> Via: SIP/2.0/TLS 192.168.0.1:41157
>>>>> ;rport;branch=z9hG4bKPj30093e5d-550d-4d4c-a9a2-22c3bd1cda7e;alias;received=1.2.3.4
>>>>> WWW-Authenticate: ...
>>>>> ...
>>>>>
>>>>> Client->Server
>>>>> REGISTER sip:...
>>>>> Via: SIP/2.0/TLS 1.2.3.4:6201
>>>>> ;rport;branch=z9hG4bKPj30093e5d-550d-4d4c-a9a2-22c3bd1cda7e;alias
>>>>> Contact: <sip:user@ 1.2.3.4:6201;transport=TLS;ob>
>>>>> Authorization: ...
>>>>> ...
>>>>>
>>>>> By the time the client is authenticated, there is no way to detect
>>>>> whether the request was coming from a natted device or not by just
>>>>> analysing the Via or Contact headers.
>>>>>
>>>>> Thanks in advance.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Kamailio (SER) - Users Mailing List
>>>>> sr-users at lists.kamailio.org
>>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>>
>>>> --
>>>> Regards,
>>>>
>>>> David Villasmil
>>>> email: david.villasmil.work at gmail.com
>>>> phone: +34669448337
>>>> _______________________________________________
>>>> Kamailio (SER) - Users Mailing List
>>>> sr-users at lists.kamailio.org
>>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>>
>>>
>>>
>>> --
>>> Best Regards,
>>> Awal
>>> _______________________________________________
>>> Kamailio (SER) - Users Mailing List
>>> sr-users at lists.kamailio.org
>>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>>
>> --
>> Regards,
>>
>> David Villasmil
>> email: david.villasmil.work at gmail.com
>> phone: +34669448337
>> _______________________________________________
>> Kamailio (SER) - Users Mailing List
>> sr-users at lists.kamailio.org
>> https://lists.kamailio.org/cgi-bin/mailman/listinfo/sr-users
>>
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>


-- 
Best Regards,
Awal
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