Security today is very important because a lot of people are assholes. Because of this most of us have heard of or use some sort of software firewall on our home PC. Many computers now come preinstalled with something like ZoneAlarm. What many people dont realize is that firewalls are so much more than that and actually are made up of several separate technologies. All firewalls are not made alike. In this paper I will cover what a firewall is and what it does, explain the differences between hardware and software firewalls including their advantages and disadvantages, briefly cover some of the technologies involved in firewalls, and help the reader to understand how to choose the right firewall for their uses.