Hi, i have no experience with H323 and NAT, but what may be of help is running a netstat -n command on machines using whiteboard when it works in an not NAT environment.
You will propably see new connections that should be added to the ruleset. UNLESS: it is UDP based. > How has my machine got hold of the internal ip address of the remote > machine? Maybe in upper layer, in the data sent by m$ application. Regards, Maciej Soltysiak
