Windows XP's Firewall - enabling and configuring it

Windows XP Service Pack 2 and above comes with a built in firewall. To check its status open the control panel.

To check the status of the the in-built windows firewall

From the Control Panel, Choose Windows Security Center,

From the Control Panel, Choose Network Connections, Right Click on Local Area Connection icon, and Choose Properties from the popup menu.

Clicking on Settings above gives you

The Exceptions Tab shows you the current list of programs that are allowed through the firewall and if you need to permit an existing program through the firewall you can add it from the Exceptions tab above.