Mandrake 10, gateway/firewall setup HOWTO

I have spent a few hours looking at google.groups to figure out how to setup a gateway & firewall on my mandrake 10 box.

Here is what I want.

Internet --- Cable modem --- Linux box --- Router --- Any clients.

1) Just to get the Linux box to forward packets.
2) The most important function I want my Linux box to do, is monitoring and restricting how much each client in the internal network are able to download. This can be done using Squid right? Is this the easiest way?
3) After I get the above working, I can play around with firewall, email, ssh, ... etc

Can someone point to me to a place where I can familiarise of how to get my gateway running.

The current configuration is this.

Internet --- Cable moderm --- Router --- Clients (Window and Linux machines)

My Linux box have two NICs. Eth0 is up and running nicely. I haven’t try to setup eth1 yet. (I am kind of scared of setting up eth1, I'll probably run in trouble again).

If you run Mandrake Control Center (mcc), and click on Security, you should have several options and 2 of the options are Firewall and Router.

Click on the Router option and you will supply which nic is internal lan and which is internet, it's that easy.

Click on Firewall and you will be able to open/close ports. Thats also quite easy.