[OpenSER-Users] port modification is sdp

[Iñaki Baz Castillo]

El Wednesday 31 October 2007 10:22:05 Konstantinos Koutsopoulos escribió:
>  The NATted device (client B) is behind a USR 9112,
>  the other machine (with openser and client B) is on an
>  academic LAN. The fact, however, is that tshark indicates
>  that the original sdp (from B) reaches port 5060 of openser
>  but the invite that is thereafter forwarded to client A
>  contains a modified sdp.

Not sure if I've understood, you said always "client B" XD

I assume client B calls from NAT. Is it a softphone?
Could you try with a softphone as B and do a ngrep o tshark in the **same** 
machine B is running and notate the INVITE message?

Then you can do a ngrep in OpenSer and inspect the received INVITE form B.

If the NAT has been fixed "by magic" then your router (in B LAN) does ALG's, 
so it rewrites the SIP message and replaces private IP with public IP and 
internal ports with NAT mapped external ports.




-- 
Iñaki Baz Castillo
ibc at in.ilimit.es