Important Internet Connection Firewall works by blocking certain types of potentially harmful network communication. However, it also blocks some useful network communication tasks (for example, sharing files or printers through a network, transferring files in applications such as instant messaging, or hosting multiplayer games). We highly recommend that you use a firewall because it helps protect your computer today. If you choose to turn on Internet Connection Firewall you can come back later for help with unblocking useful network communication tasks. For more information, please refer to the Frequently Asked Questions About Firewalls.

The steps below tell you how to make sure the Windows XP firewall is turned on. If you have a different configuration, a home network, a different version of Windows, or if you encounter problems during the steps, see the Frequently Asked Questions about Firewalls.

To turn on the Internet Connection Firewall

1. Click Start, and then click Control Panel
    
2. Click Network and Internet Connections, and then click Network Connections.
   
   
   Click Network and Internet Connections
   
   
   Click Network Connections
   
   

   Note: If the Network and Internet Connections category is not visible, click Switch to Category View on the upper left of the window.

   
   Switch to Category View
   
    
3. Under the Dial-Up or LAN or High Speed Internet heading, click the icon to select the connection that you want to help protect.
   
   
   Select a connection
   
   
4. In the task pane on the left, under Network Tasks, click Change settings of this connection. (As a shortcut, you can right-click the connection you want to help protect, and then click Properties.)
   
   
   Change connection settings
   
   
   Alternatively, right-click the connection, and click Properties
   
   
   
   
5. On the Advanced tab, under Internet Connection Firewall, check the box next to Protect my computer and network by limiting or preventing access to this computer from the Internet.
   
   
   Check the box to protect your computer and network
   
   

After you check the box and close the Properties window, the firewall is turned on. The firewall may interfere with some network operations such as file and print sharing, networking-related programs, or online games. For more information about fixing these issues, see the Frequently Asked Questions page listed below.

If you have more than one computer, want more technical information, or just want to learn more about Internet firewalls, see the Frequently Asked Questions About Firewalls page.