OK here is what I want to do.......

I want to use a Red Hat 8 or 9 box to act as a Router between a unsecure "Real IP" network and a secure DHCP NAT Network. I am planning to use a box with two ethernet cards, One configured for each network.

Question:
Am I right in thinking if I set the default gateway on the box to the normal intenet gateway on the unsecure network. Then use the secure ip address of the box as the gateway for all the machines on the secure side.....will this work?

Have I missed something?

Any thoughts on this will be appreciated

On your Linux system, assign a default gateway only for the NIC that will be connected to the Internet. The NIC that connects to your local network does not require a default gateway.

You will also need to enable ip forwarding

edit /etc/sysctl.conf and set
net.ipv4.ip_forward = 1

I am sure you will indeed use iptables to filter traffic.

Thank you

are there any other consideration I should take into account?

DNS perhaps, DDNS if you so please

Squid proxy if you want to regulate access... anything else???

I thing that will hold me for now.....see how far I get