How to Provide NAT between 2 Internal Subnets

[mdwu]

I have 3 nic on my ISA Server
nic 1 - Internet (209.1.1.1)
nic 2 - subnet A (192.1.1.1)
nic 3 - subnet B (172.1.1.1) also connects to corp intranet with other subnet addresses 910.1.1.1, etc)

This is what I need,
1 - Provide Internet access for subnet A only
2 - Provide Server Publishing from subnet A
3 - Provide access between subnets with NAT

For Item 1 and 2, I think I got it to work. However, I just don't know how to set it up to allow internal subnet access with NAT. Because of corp policy, when the subnets access each other, it will need to be NAT to each other's ip range.

Bascially, in order for subnetA to access subnetB resources and the corp intranet resources which subnet B is connected to, all traffic from subnet A need to be NAT by subnet B's nic. I only want this to be done between the subnets, because obvously, i don't want outside internet user to have access.

I read about the Tri-Homed settings, but they show routing, which doesn't NAT the addresses.

is this possible.

 

[PhillyCheeseSteak]

If I understand this correctly, you want all access from either subnet to be "hidden" when accessing the other subnet, correct? i.e. you can't tell which users from the subnet are accessing your computer.

If this is the case,you can't do this with just one win box. You'd either need two more windows 2000/2003 routers enabled for nat or a cisco router.

Phil.

 

[mdwu]

Thanks

Actually I do. This is how it's setup. Obviously, my subnet is all pointing to the ISA Server. so the ISA is the 192.168.x.x router. On the 3rd nic of the ISA, which is 172.1.1.1 is connected to the 172.x.x.x router. Which mean my 3rd nic is not the router for 172.x.x.x subnet. The 172.x.x.x subnet do have another Win2k Router in between and then from that router to my ISA.