In today’s computing age, having a firewall set up on your PC is a necessity. In fact, a firewall accompanied by a good anti-virus utility is the best defense you can provide your computer from the plethora of potential threats on the internet. At the time of this writing, we have just gone through the notorious MSBlast worm virus, a virus which spread itself around the internet quickly by scanning for open ports across the internet and entering open PCs. Once a virus like this is inside your computer, its there. Unless you routinely scan your computer for viruses, that virus is free to do its work on your machine. Obviously, your first line of defense is a good firewall. A firewall will keep these pesky worms out of your computer in the first place.

A firewall is a tool which sits in between your computer and the open network and scans incoming traffic to ensure that it is legitimate and from only the sources which you allow. Firewalls can be either software-based or hardware-based. Many network hubs and routers come with built-in firewalls. The most popular type, though, is the software-based firewall. This software, when installed, will typically start up when you boot up. Once it is up and running, it will scan all incoming traffic on all ports and alert you if it detects potentially unsafe traffic.

Firewalls are particularly necessary for users who use cable or DSL to access the internet. Such “always on” connections provide a full time open road for traffic into your PC. Even when you are not surfing the internet or checking your email, your computer is online. These types of internet connections use a limited and well-known range of IP addresses. These are continually scanned for open doors by people up to no good. Users who access the internet via dial-up have less of a threat because when they are offline there is no outside route into the computer. However, when you are online, you are up for attack. The chances are not as great as those who use a high-speed connection, but the threat is still there.