[OpenSIPS-Users] rPort question

[Bogdan-Andrei Iancu]

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"