Free NAT for NT?

["Ryan Russell" <Ryan.Russell () sybase com>]

Anyone aware of any free Network Address Translation (NAT)
software for Windows NT?

I'm writing a chapter on NAT, and the publisher is calling for examples
in Linux, Cisco IOS, and NT.  The first two are easy, but I'm only aware
of commercial solutions for NT.  (No, I'm not under the impression that
the Cisco implementation is free, but since there is only one choice, it's
a bit of a moot point.)

I prefer free solutions, so that readers can obtain and play with the
technology more easily.  Barring that, I'll go after low-cost, or possibly
higher-cost but with downloadable demo.

                         Ryan