Computer viruses! Worms! E-mail viruses! Trojan Horses! The media is always full of stories about computer viruses infecting computers all over the world, or companies scrambling to fix security holes in their software by releasing security updates. What can businesses or individuals to protect their computer? Installing a firewall may be one answer.



While the first computer viruses were transported from computer to computer by floppy disks, computer viruses today can cover the globe in the blink of an eye over the Internet. And they've probably made it to your computer. You have likely had to deal with the consequences of spyware and other malicious programs that had have crawled onto your computer while you were browsing the Internet. And as a consequences, you've probably spent hours and hours trying to get rid of all the spyware and other malicious programs that have taken up residence on your computer.

Even if you think your computer is virus free, you are probably wrong. That is why spyware and viruses are so dangerous; you could be using your computer with no idea that they're there.

A firewall puts a wall between your home network and the Internet. Just like a real firewall keep fire from spreading from one area to another, a software firewall tries to keep computer viruses from spreading from the Internet onto your home computer or home network.

The firewall itself is a piece of software that is usually run on your router or cable moden. By attaching itself to this hardware, the firewall is the first thing any incoming traffic from the Internet meets.

The firewall's job is to act to filter all of the traffic from the Internet that comes onto your home network. Whenever a network packet tries to come onto your home network, it has to make it by the firewall first. The firewall will analyse the packet to make sure it isn't a virus or some other undesirable communication. If the firewall gives it the all clear, it will let the packet continue on its journey to your home network.

The firewall will use user-defined parameters and automatic parameters to decide whether the traffic should be let through or labelled dangerous and blocked. As the user, you could configure the firewall to block all traffic coming from a specific IP address. Obviously, you won't be able to do this for all the malicious sites on the Internet: this list would be far, far too long!

For this reason, the firewall will automatically screen incoming traffic to make sure it corresponds to the kind of traffic you would want to receive by running it through a set of predetermined parameters. For instance, the firewall will usually let traffic sent from a website through to your computer, but it will not let someone remotely login to your computer.

No matter what software or hardware you use, you will always be putting your computer at risk when you connect it to the Internet. You can limit this risk as much as possible, however, by using a firewall. A firewall will let you access all the wonderful resources of the Internet without staying awake all night worrying about your home network.