[OpenSIPS-Users] [NEW] More on NAT and TCP handling

[Bogdan-Andrei Iancu]

Hi all,

OpenSIPS trunk (future 1.7 release) has a new TCP extension to prevent 
opening TCP connection to destination behind NAT.

The main addressed scenario is : (1) user from behind NAT registers with 
OpenSIPS, (2) the TCP conn is lost because UAC reboot, net issues, 
firewall issues, opensips reboot, (3) opensips needs to send a call to 
user, but there is no TCP conn available anymore and a new one cannot be 
opened.
In such a case, it is efficient to detect such cases (we when based on 
user location that the destination is TCP and nated), so we can avoid 
the penalty of trying to open an impossible TCP conn ; also we can force 
the "unregistration" of the user, as it is not reachable anymore.

For more details on the technical side (how to do it) and a small script 
sample, see:
         http://www.opensips.org/Resources/DocsCoreFcn#toc80



Best regards,
Bogdan

-- 
Bogdan-Andrei Iancu
OpenSIPS solutions and "know-how"