This should be fairly simple to set up, depending on your Linux distro... Mandriva has an option in a config file that you need to modify in order to activate ip forwarding (just add FORWARD_IPV4=yes in /etc/sysconfig/network)
However, this would mean no firewall, no protection, no advanced thingies. I've been using shorewall as a firewall for a few years now and it is pretty simple to configure, there is extensive documentation on their site (www.shorewall.net
), and works with every distro, provided the requirements are met. Configuring ip forwarding is just a matter of setting IP_FORWARDING to On in /etc/shorewall/shorewall.conf.
Read here for some more info about setting up networking: http://www.linux.se/doc/HOWTO/mini/H...i-HOWTO-3.html