[OpenSIPS-Users] rPort question

[Bogdan-Andrei Iancu]

On 07/08/2011 07:45 PM, José Pablo Méndez Soto wrote:
> Thanks a lot Bogdan.
>
> I follow the use of rPort all the way explained here. What I don't 
> understand, is, if the received and rport parameters are filled in by 
> the UAS that gets the request, how is that useful to the UAC that 
> originated it when the reply is routed back to it? What situations may 
> happen so that the UAC needs this info?
The proxy adding the rport + received is doing that for itself - it is 
populating that info in request (when received) so that the proxy will 
know at reply time where to send it back.

Regards,
Bogdan

>
> NAT of course, but what would cause the SIP UAC not to process the 
> reply packet correctly? Is it the info contained at layer 5? or the 
> socket disruption at layer 3?
>
> *José Pablo Méndez
> *********
>
>
> 2011/7/8 Bogdan-Andrei Iancu <bogdan at opensips.org 
> <mailto:bogdan at opensips.org>>
>
>     Hi José,
>
>     'rport' VIA param is to be used in NAT situations. As the VIA hdr
>     is used for routing back the replies, if the caller is behind nat
>     (and its VIA with a private IP), the routing back of the reply to
>     it will not be possible.
>
>     The way rport works it is very simple - this param (together with
>     "received") are added to the top most VIA hdr if this VIA
>     indicates a different IP:port than the src ip:port on net level.
>     The received and rport are added to contain the layer 3 IP and
>     port (which can be used later for routing back the reply).
>
>     Regards,
>     Bogdan
>
>
>     On 07/06/2011 01:55 AM, José Pablo Méndez Soto wrote:
>
>         Hello,
>
>         Can anybody explain how the rPort works in conjunction with STUN?
>
>         I have gone through the RFCs but can't make sense out of  a
>         packet capture I have over here. If possible, I would like
>         someone to explain how the layer 3 and 5 IP addresses will
>         flow and be re-writed when SIP works behind a NAT (Just one
>         side behind NAT  and the other publicly available lets say).
>
>         Thanks in advance,
>
>
>     -- 
>     Bogdan-Andrei Iancu
>     OpenSIPS eBootcamp - 2nd of May 2011
>     OpenSIPS solutions and "know-how"
>
>


-- 
Bogdan-Andrei Iancu
OpenSIPS eBootcamp - 2nd of May 2011
OpenSIPS solutions and "know-how"

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