I agree with jdc on this
I would love to see linux102 on this, maybe with dynamic firewalls rules. Its all laid out cleanly, simple to follow, and command line based, so any distro should behave exactly the same. I would have to say, its by far one of (if not the) best guides for learning iptables. There are many with more "readability" and more with more "content" but very few match this guide in terms of content AND content access.