How to enable the Windows XP firewall

Windows XP service pack 2 has a more advanced firewall than earlier versions. The method you use to enable the firewall depends on the version you have. If you are not certain what service pack level you have, see How to Determine Your Service Pack Level.

Windows XP, windows XP SP1

Select Start, click Networking and Internet Connections, then click Network Connections.
Right-click the connection on which you wish to enable the ICF, then on the pop-up menu select Properties.
Select the Advanced tab, and then click to check the Protect my computer or network check box.
Click OK to close the Properties dialog, and then close the Network Connections window.

Windows XP SP2

Select Start, click Run, type firewall.cpl, and then hot the Enter key or select OK.
On the General tab, click On (recommended), and then click OK.