You may try enable IP routing. This post may help too.
Setup Vista as routerLegrandin The Vista is not designed as router. However,
you may try it by enabling the IP routing. The following links may help, How
to setup XP as a router ...
Bob Lin, MS-MVP, MCSE & CNE
Networking, Internet, Routing, VPN Troubleshooting on
How to Setup Windows, Network, VPN & Remote Access on
"BChirhart" <BChirhart@discussions.microsoft.com> wrote in message
>I have a Vista Ultimate PC with 2 NIC's on 2 seperate networks.
> and 20.0.
> How can I set up routing between these two networks through the Vista PC?