[OpenSER-Users] How to detect if both UAs are from the same LAN

Raúl Alexis Betancor Santana rabs at dimension-virtual.com
Sat Jun 14 15:03:36 CEST 2008


El Sábado, 14 de Junio de 2008 11:38, Juha Heinanen escribió:
> Raúl Alexis Betancor Santana writes:
>  > Uff .. double nat situations are not very common ... but yes it could
>  > happens,
>
> actually double nat is quite common.  one can have dsl subscription
> where nat is done in the modem and wlan ap behind it that does another
> nat.  or gprs internet access where operator gives nated address and
> another nat box at customer premise.

Only the second case could be common, the first one you mention (and AP doing 
a second nat inside the same network) I consider it a faulty desing of a 
network, if you have AP's in your network, you are not forced to put them to 
work as a NAT router, but that is another question.

Coming to the original theme, it is possible to solve the problem of two UAC 
behind the same NAT no matter if there are one, two or 1 millon NAT's behind 
the first one.
It's obvious that the simplest solution it's to alway force RTPproxy use in 
case of nat, but you could also test if both UAC are behind the same NAT 
(first level of ..) and don't send them to RTPProxy, because on 99% of times, 
they could reach eachother.

-- 
Saludos.

Raúl Alexis Betancor Santana
Dimensión Virtual S.L.




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