[SR-Users] Kami as NAT traversal + FS as media

[Daniel-Constantin Mierla]

Hello,


On 05.01.18 12:33, Yu Boot wrote:
> Thanks for an answer? but what I want to do (already done :)) is
> totally opposite to your solution.
>
> The main thing I wanted, so I don't need to open 5060/UDP on
> FreeSwitch for (entire world), BUT at the same time АЫ should work
> with RTP traffic directly, no matter is it NATed UAC or not.
>
> This kind of "NAT traversal" (call it RTP NAT traversal :)) and UAC
> registrar are on Kami side. FS is pure softswitch here.
>
>
> What I did to perform this is replace
>         rtpproxy_manage("co");
>
> with
>
>       fix_nated_sdp("10");
>
> Now it works exactly as I wanted. Thanks for advice.

this is not fixing anything from RTP point of view, or better said, it
is not something that is working alone with a symmetric nat. You rewrite
the SDP IP with source IP, but it should just work the same without
rewriting it. For a symmetric nat the media port advertised in SDP is
not going to match the allocated port for the rtp flow in the public
side of the nat router -- if it does, can be just a luck, which is not
going to work forever, especially if there are many sip clients behind
same nat router.

Anyhow, what I meant is to fix the SIP headers (not the SDP), so you do
SIP routing properly for requests within dialog. The port 5060/udp for
FreeSwitch should be open only for traffic from/to kamailio and doesn't
have anything to do with the SDP and RTP, nor eliminated if you do nat
fix for the headers...

Cheers,
Daniel
>
>
> 04.01.2018 12:42, Daniel-Constantin Mierla пишет:
>> Hello,
>>
>>
>> On 25.12.17 10:16, Yu Boot wrote:
>>> Hello. I want to implement the following scheme:
>>>
>>> Kami takes inbound call, replces SPD for correct NAT trversal and
>>> forward that call to FS. Kami should NOT be in RTP stream. Is it
>>> possible? Any advices?
>>>
>> Kamailio should not touch the SDP if it is not going to do the RTP
>> relaying with rtpengine or rtpproxy. Just leave it untouch, freeswitch
>> will handle what is needed in this regard.
>>
>> What you have to do is to fix the signaling for nat traversal, which may
>> mean to use path module for handling registrations as well as doing
>> set_contact_alias() as well as handle_ruri_alias(), so you can route
>> requests within dialog.
>>
>> Cheers,
>> Daniel
>>
>

-- 
Daniel-Constantin Mierla
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