The firewall program will allow you to stop uninvited access to your computer.

Adding a good firewall program to your computer can also help protect it.

Although many people do not realize it, Windows XP comes with a built-in firewall program that you can use.

A good firewall program can block undesired outgoing Internet traffic.

A laptop used for wireless access should also be secured with other standard safety measures, including a firewall program.

If you use a different firewall program, check your manufacturer's Web site or technical support hotline for information on compatibility.

Use a firewall program that warns you about outgoing connections that botnets make to communicate with control software.

Q. Is it worth it to buy a firewall program for my Mac?

Microsoft's Web site instead advises installing or turning on a firewall program.

Most companies that make firewall programs frequently issue software updates to keep your firewall prepared.