Redhat gateway issue - Internet access from a subnet

[<menonrr jmu edu>]

Hello,

I have a network topology like this.

Internet---| Redhat GW|------192.168.1.0 network-----|X
Router|----172.16.4.0 network.

I can access the internet from 192.168.1.0 network. I put the
DNS address of Interenet provider in the clients to access the
internet. 

While I can ping any internet address from 172.16.4.0, I
cannot access internet from the only Windows 2000 client in
that network. When I ping 'www.google.com' it says "unknown
host" or something. The redhat GW is not a DNS or DHCP.

I would appreciate some insights and advices.

Thank You.
Menon