Firewall Q & A
Firewalls can protect both individual computers and corporate networks from hostile intrusion from the internet. This paper tries to answer some questions regarding firewalls.
Internet Firewalls Frequently Asked Questions
A firewall is a system or group of systems that enforces an access control policy between two networks. The actual means by which this is accomplished varies widely, but in principle, the firewall can be thought of as a pair of mechanisms: one which exists to block traffic, and the other which exists to permit traffic. Probably the most important thing to recognize about a firewall is that it implements an access control policy.
A complete overview of firewalls, from placement to what to block and common configuration errors.