Net meeting by Microsoft is not suppoted by NAT ..... this is the major
problem
NATs violate many of the assumptions of the Internet Protocol. It's
unrealistic to expect many kinds of IP applications to work in the
presence of NATs, unless they were specifically designed to do so.
And while it might seem desirable to make all applications NAT-tolerant,
NAT-tolerant design often imposes significant barriers to the
performance and scalability of applications, and (due to the need
for intermediaries to tunnel through NATs) to deployment of such
applications.
Keith