Beginners Guide to Computer Firewalls

Today I want to talk about computer firewalls. I am sure most of you have heard about computer firewalls before but may not know just what they do or how they work.

Basically what a firewall does is control the flow of data in and out of your computer. It can also monitor your computer to detect if anyone is trying to access your computer.

There are two types of firewalls. Software and hardware. The software firewall is a computer program that you would load just like any other program. The hardware firewall is built into a high speed modem or router.

The software and hardware firewall both control the flow of data the same way. By the manipulation of ports. There are a number of different ports on your computer and every program that you have on your computer that accesses the internet has a port assigned to it.

There are three type of port status "open" "closed" and "stealth" an open port means that any computer or program that checks a port that is open tells the computer or program that there is a computer at that IP address

If a port is closed and another computer or program checks that port it can tell there is a computer at that IP address but the port is closed. And if a port is set to stealth when another computer or program checks that port it won't even know a computer is at that IP address because it found no port to check.

If you have a DSL or Cable modem internet connection you will not need a software firewall because a hardware firewall is already built into your modem. Hardware firewalls are usually configured to a medium setting which is good for most situations. There may be some instances where you might need to open a port manually if you use a lot of programs that access the internet. To do this follow the instructions of the hardware manufacturer

If your firewall is set too high you may not be able to access the internet and if it is set too low it won't protect your computer.

If you are still using a dialup connection then if you have Windows XP you can use the software firewall that comes with it or you can download a free firewall from the internet. There are a number of free ones to choose from.

To check the current status of your ports go to http://www.grc.com and click on "Shields Up"