Do I have to enable bridge if I want to make Linux box (PC) as Router
(4-port NIC for local LAN and 1-port NIC for WAN)?. I have two NIC
cards, one is 4-port NIC card which is to connect all four local PC's
for Net connection and one port NIC connected to DSL/Cable MOdem. Do I
have to enable Bridge?. In this case how do I have to name the ethernet
ports, like eth0, eth1, eth2......eth4?.

Also if I want to access the Router over the LAN to configure the
Router parameters, do I have to connect one more NIC or Is there any
alternative way is there?.

Thanks.