Exactly. A slight oversimplification is that all straight NAT does is
change the IP address in the header. A -> B on the way out and B -> A on
the reply.
Proxy-NAT needs to set up a stateful socket system where A becomes
B:socket1, and C becomes B:socket2, etc - so a reply to B:socket1 is
translated back to A. And since it is dynamic assignment of sockets (you
can have more than one request from the same IP at one time too) you
have to keep track of all the translations you've done, at least until the
connection is dropped.
-MZ
-- Livingston Enterprises - Chair, Department of Interstitial Affairs Phone: 800-458-9966 510-737-2100 FAX: 510-737-2110 megazone@livingston.com For support requests: support@livingston.com <http://www.livingston.com/> Snail mail: 4464 Willow Road, Pleasanton, CA 94588