by Greg Schwartz

Created on: March 18, 2010

Introduced as part of Service Pack 2, the Windows Firewall is a free packet filtering firewall for Windows XP users.  Windows Firewall replaces the previous Internet Connection Firewall.  It is simple to run and can easily be configured to meet most users' needs.

Windows Firewall comes turned on by default, which is good for most users.  The firewall keeps out unsolicited Internet traffic and block attempts by hackers to access your computer.  On a home network, enabling the firewall on the computer with the Internet connection will provide security for the rest of the computers on your network as well.

To access the Windows Firewall settings, just open the Control Panel and click the Windows Firewall icon.  (You can also get to the same screen from inside the Security Center.)  From here you can turn the firewall on or off, as well as create and delete exceptions.  You can also set the firewall to ignore all exceptions - this is a good setting to use when connected to a public or unsecure network.

The Exceptions tab is where you can manage programs or services that may need to bypass the firewall in order to function correctly.  One service that has a pre-configured exception is File and Printer Sharing.  If you have installed a program that needs to access your network or the Internet, and the program isn't working right, you may need to create an exception for it.  Be aware that creating exceptions increases the chance of something unwanted accessing your computer.

Similarly to creating an exception, another way to bypass the firewall is to open a port.  Some ports are open by default, but you can open more if you need them.  Only open a port if you are sure you know what you are doing - this can be a severe security risk for your computer and your network.  Whereas exceptions are only used for the programs you created them for, any application can access a port that you have left open.

Unlike the Windows Vista Firewall, the XP Firewall is not bidirectional.  It will only block incoming traffic; it won't do anything to stop outgoing traffic.  If you have the firewall enabled and you try to read your email or load a web page, the firewall won't stop either of these activities, because they were solicited by you.  However, the firewall will keep out unsolicited attacks and other attempts by hackers to break into your computer.

If you are connected to a home network with a router, there is a good chance your router has a built-in firewall.  If so, you can turn off the Windows Firewall.  On a home network, the Windows Firewall sometimes does too good of a job, and stops your computers from communicating with each other.

The Windows Firewall is a good free firewall, if you don't have another firewall in place.  If you have Windows XP but don't have Service Pack 2 installed, you can download it from the Windows Update website, or just turn on Automatic Updates.

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