Configuring a firewall has never been a trivial task, but more recent versions of Windows Firewall (though still pre-Windows Vista) make the task a bit easier. The concept is simple: The firewall blocks all incoming traffic except the entities that you list as exceptions. An exceptions list (aka filter) defines specific network traffic that you don’t want blocked: program and port traffic that you choose to allow through the firewall. When you add an exception to the exceptions list, the firewall permits all traffic to that program or port. The long-established best practice of firewall security is to block everything and allow only minimal exceptions. For each exception, you should use the most restrictive setting that will still allow access.
Note: The Windows Vista firewall—which includes some key features that go beyond those of the Windows XP Service Pack 2 (SP2) firewall, such as the ability to block outbound traffic—won’t be covered in this article. For information about the Vista features, see Jeff Fellinge’s article “Vista’s Firewall,” August 2006, InstantDoc ID 50377. . . .
