Original Article: Securing Your Computer with a Firewall

Many people do not know what a firewall is or why they should be using one. A firewall is typically a program or piece of hardware that stands between your computer and the internet, or your local area network (ie. your company’s network). A good firewall sifts through all requests made by your computer or to your computer. If you visit a website, a firewall would check to make sure that the website does not attempt to gain access to your computer.

There are two ways that a firewall can secure your computer. One way is to make sure that no one is able to get into your computer from the outside world. Hackers or computer users with malicious intent routinely perform scans across the internet to see what computers have open ports. Whenever a program on your computer needs to access the internet it opens up a port to send and/or receive data through. It’s like opening a window to let air in and out of a room; a burglar can easily get into your house through that open window.

The other way a firewall secures your computer is to make sure that no unauthorized program on your computer tries to access the internet or another computer. Sometimes people may put trojans, or backdoors, into programs. A trojan infects the computer it is loaded on and dials out to the internet to carry out it’s objective. Computers infected with trojans are called zombies if they are used to perform an attack on websites, such as the semi-recent string of Denial of Service (DoS) attacks on websites like CNN and Yahoo. Some trojans will collect your personal information, such as credit card numbers, and then send them to the virus creator. A firewall can alert you when a program is trying to access the internet and if it as legitimate program such as Internet Explorer or AOL Instant Messenger you can allow it to connect to the internet. Otherwise you can choose to deny the program access if you do not know what it is. (Note: Some programs are used by windows and denying them access to the internet can cause your internet connection to not work properly. All you would have to do is allow the connection the next time the program asks to connect to the internet.)

One thing to make sure when choosing a firewall is whether it blocks both incoming and outgoing connections on your computer. Tiny Personal Firewall and Zone Alarm will allow you to block both types of connections, while Black ICE Defender will only block incoming traffic. Tiny Personal Firewall is free for home use, as is a scaled down version of Zone Alarm; while Black ICE is not free.

Note: Tiny Software no longer offers a free firewall, though Zone Alarm still does.

Originally posted on Infohuts.com and TechHelpCenter.com, which has been folded into Shiwej.com.