A firewall is software or hardware that checks information coming from the Internet or a network, and then either blocks it or allows it to pass through to your computer, depending on your firewall settings.

A firewall can help prevent hackers or malicious software from gaining access to your computer through a network or the Internet. A firewall can also help stop your computer from sending malicious software to other computers.

You can customize most settings through left pane of the Firewall applet in Control Panel.

windows 7 firewall

1. Turn on Windows Firewall.
This setting is selected by default. When Windows Firewall is on, most programs are blocked from communicating through the firewall. If you want to allow a program to communicate through the firewall, you can add it to the list of allowed programs. For example, you might not be able to send photos in an instant message until you add the instant messaging program to the list of allowed programs. To add a program to the list, see Allow a program to communicate through Windows Firewall.

2. Block all incoming connections, including those in the list of allowed programs
This setting blocks all unsolicited attempts to connect to your computer. Use this setting when you need maximum protection for your computer, such as when you connect to a public network in a hotel or airport, or when a computer worm is spreading over the Internet. With this setting, you are not notified when Windows Firewall blocks programs, and programs in the list of allowed programs are ignored. When you block all