A good NAT for Linux

["Steven Osman" <sosman () terratron com>]

Anyone know of a good NAT server and proxy server (either together or as
separate packages) for Linux?

Basically what I'm trying to achieve is this :

Taking one single IP address (say, from a dialup or a DSL connection) which
may or may not be static, and fanning it out to a number of workstations
(like 6 or so), and providing them as much freedom as possible to run
different applications.  I was hoping that between a www and ftp proxy, and
a socks proxy, I'd have most applications covered, and then I'd use NAT for
any off-the-wall applications that may be running.

Any ideas?

Steven
p.s. If it's free, that's better of course :)