I've had a fantasy of setting up a Linux firewall computer to protect our Windows computers here, or failing that, at least setting up a Linux machine as my primary internet computer. Need plenty of advice if you can offer it, I don't really know much about Linux.

Built up a MODT (mobile [CPU] On Desktop) computer using a laptop hard drive, because I wanted to try making a low-energy computer for a change. Has no onboard CDROM or DVD, but have acquired a nice USB2 external that succeeded in booting Knoppix and performed a Knoppix HDD install, version 5.1. It's an all-in-one board and I've installed no cards and want to refrain from it.

After addressing a small issue with permissions discussed in the HDD install forum here, I managed to perform an apt-get update and upgrade, and got Knoppix to configure my network chip so I can now go online with the new box. So far good. BTW, using a Zyxel X-550 router.

First big question:
This Mobo has only one LAN connector. Do I need more than one network connector to properly use this box as a firewall? I don't want to add another PCI card if I can avoid it. (This question pretty much shows how much I know I'm sure.)

Other big question:
What should be my next steps? I'm a Linux novice really, and I've always run away from networking issues. Can anybody describe or direct me to some infos or resources for how to easily as possible achieve my goal, or what I need to look at? I'm really trying to keep it simple and avoid steep learning curves if I can. At least for now.

Thx for your attn., the minnow