ZoneAlarm is designed to protect your DSL or cable-connected PC from hackers. This program includes four interlocking security services: a firewall, an Application Control, an Internet Lock, and Zones. The firewall controls the door to your computer and allows only traffic that you understand and initiate. The Application Control allows you to decide which applications can and cannot use the Internet. The Internet Lock blocks Internet traffic while your computer is unattended or while you are not using the Internet, and it can be activated automatically with your computer's screensaver or after a set period of inactivity. Zones monitor all activity on your computer and alert you when a new application attempts to access the Internet.