I'd like to thank him for allowing me to update his work. Firewalls have gained great fame recently as the ultimate in Internet Security. Like most things that gain fame, with that fame has come misunderstanding.
Any feedback is very welcome.
I am human, and prone to making mistakes. If you find any, fixing them is of my highest interest. I will try to answer all e-mail, but I am busy, so don't get insulted if I don't. This document is meant as an introduction to how firewalls and proxy servers work. I am not, nor do I pretend to be, a security expert.