Firewalls are tools, built into either hardware or software, that prevent your computer from engaging in unauthorized and potentially dangerous exchanges with other computers.
Most computers come with firewalls that users can turn on to increase the security of their computers.
How you can use this tip
Look up the term “firewall” in your computer’s Help menu. That firewall explanation should tell you more about how the firewall works and lead you to the Control Panel, or System Preference, where you can turn the firewall on.
You can also find information on built-in firewalls on the Internet for Windows 7, Windows XP and Mac.
One small complication: if you do use a firewall, make sure that the software you installed and use can communicate through the firewall. This is easier to do than it might sound; modern firewalls ask you if you want to permit software to send and receive information over the Internet the first time the software in question tries to do this.
If you use a router between your Internet connection and your computer, you should have the protection of a firewall built into the router – most routers have firewalls built in. You can still use the firewall in your computer, though, as an extra measure of protection.