Configuring, Managing, and Troubleshooting an Internet Connection Firewall (ICF)

What was originally billed as the Internet Connection Firewall (ICF) is called the Windows Firewall since SP2. Windows Firewall is a personal firewall, stopping undesirable traffic from being accepted by the computer. Using a firewall can avoid security breaches as well as viruses that utilize port-based TCP or UDP traffic to enter the computer's operating system. For computers that use broadband Internet connections with dedicated IP addresses, the Windows Firewall can help avoid attacks aimed at disrupting a home computer. Even people with dial-up Internet connections can benefit from added protection.

Configuring a Windows Firewall After Installing SP2

The Windows Firewall can be enabled or disabled separately for each connection. In doing so, you are able to use Windows Firewall to protect a computer connected to the Internet via one adapter, and not use Windows Firewall for the adapter connected to the private network. To enable the Windows Firewall, click Start, then Control Panel. Open the Network Connections applet in the Internet and Network Connections category. Right-click the connection icon and select Properties. Click the Advanced tab and click the Settings button under the Windows Firewall section. In the Windows Firewall applet, click the On radio button. Click the Exceptions tab and select the applications that will not be blocked by Windows Firewall. If an application is not listed you may add it by clicking Add Program. If a particular TCP or UDP port needs to be enabled, click the Add Port button. And if you need to change the configuration options for an existing program, click the program and then click the Edit button.

If you click the Advanced tab, you should select the boxes next to any connections that link to the Internet, and clear the boxes next to any connections to a private network. With the Internet connection box selected and the item selected, click the Settings button to enable incoming services to pass through the firewall filter.