We are setting up Debian "sarge" stable 3.1. Intended use Internet web server, email server, DNS and file sharing for remote backup solutions. Hardware consists of external high speed cable modem. Cable modem 4 port router hardware firwall with DMZ port. Should we set up our intended server box on the DMZ port on the router considering the above intended uses?
I personally wouldn't use demilitarized zone on a network. You are basically opening that single server and every port on it. If you aren't adverse in iptables, you are risking that server to full blow port scan and brute force attack on very port. Just port forward the necessary ports to the linux server and be done with it.