When you connect your PC to the Internet either through cable, dial-up, or DSL, it is like China prior to the Great Wall. Anyone can invade your PC, and plunder, pillage, and destroy content on your PC. A firewall acts just like the Great Wall of China. When installed, it acts as a barrier between your PC and the outside world. It prevents unwanted and unauthorized access to your PC over your Internet connection.

Firewalls come in two basic forms:

• Hardware firewalls - hardware firewalls are a piece of hardware, like a PC, that gets installed between your PC and your Internet connection. Literally, a cable from your cable or DSL modem gets connected to the hardware firewall. Another cable is connected from the hardware firewall to your PC. When done, the hardware firewall acts as a barrier between your PC and the Internet. It lets you get out to the Internet, but it does not allow unauthorized access from the Internet to your PC. Many cable, DSL, and wireless routers/switches have firewalls built into them.


• Software firewalls - A software firewall serves the same purpose as a hardware firewall. It, however, is software that gets installed directly onto your PC. The software monitors all inbound and outbound Internet traffic, and creates a software barrier between the Internet port into your PC and everything else on your PC. Once installed, it lets you get out to the Internet, but it does not allow unauthorized access from the Internet to your PC. Software firewalls have an advantage in that they can implement rigid controls over what software installed on your PC will be allowed to access the Internet.

Many people use both a hardware firewall and a software firewall. It is similar to having a fence to protect access to your yard, and then a front door to protect access to your house. Everyone should use at least one firewall, hardware or software. If you have a laptop, you should use a software firewall. That way the firewall goes with you, wherever you go, protecting your PC.