Very Computer

could someone please direct me to the most comprehensive and/or easiest to
understand source on building a linux firewall. I am running a lone box (no
networked computers) through a cable modem connection on device eth0. I
really need the help, thanks

Get the book "Linux Firewalls" by Robert L. Ziegler.  It covers ipchains
really well.

This built me a tight ipchain firewall rule set
   http://linux-firewall-tools.com/linux/firewall/index.html
I used DENY, hardcoded external addresses, logged everything.

As part of the instruction and if you read the script, it will
give several suggestions as to where you install the firewall.

If you are running Redhat 6.1 put this in your browser
        file:/usr/doc/ipchains-1.3.9/HOWTO.html
if not look on your disk.
                            locate ipchains | grep HOWTO
if locate complains do a          updatedb

--
The warrenty and liability expired as you read the message.
If the above breaks your system, it's yours and you keep both pieces.
Practice safe computing. Backup the file before you change it.
Do a,  man every_command_here, before doing anything or running a script.