firewall ??

[Bobby Knueven <knueven.7@xxxxxxx>]

I am getting ready to build my first firewall, using Fedora Core 2. I 
have read a lot of tutorials, but all of them are for firewall with NAT 
enabled. What do I do if I don't need NAT. For example, I have a 
network with 50 Class B Ip's we use a default gateway supplied by our 
University and DHCP to distribute the IP's. So the only thing I really 
need to do is firewall my 50 IP's from the outside world while 
continuing to use our given IP's and gateway. Any thoughts on how to 
set this up would be appreciated.

One more question, when connecting the outgoing NIC from the firewall 
to the rest of the network do I need to use a crossover cable or will I 
specify that the NIC is supposed to be outgoing in firewall 
configuration?

Thanks for the help.

Bobby K