Having a firewall on computers that connect to the internet is now essential given the recent attacks on computer systems not so protected. Windows XP has its own simple firewall built in that can be used if you don't want to purchase or download a more sophisticated one.
To enable the built-in firewall in Windows XP you first need to go to My Network Places. At the top of this window you should find an entry called Local Network. Right click on this and select Properties.
You will next see a window showing your network connections. Select the adapter that is used for your internet connection.
Now go into the properties dialog and open the Advanced page. Make sure that Internet Connection Firewall is selected.
Finally, select OK to activate the firewall.
This article written by Stephen Chapman, Felgall Pty Ltd.