In part one I wrote about the importance of anti-virus protection. However that is not the only tool you can use to protect yourself from online nasties.  A Firewall is also a good way to stop hackers and viruses gaining access to your computer.

The strength of the Internet is the ability for one computer to talk to another, anywhere in the world. Unfortunately this is also its weakness. When you are connected to the Internet you have a unique address, very similar to your physical address. No one else has the same exact physical address as you, so if someone addresses a letter to that address, it will be delivered to you (I’ll refrain from making any unfair remarks regarding the postal service).

Hackers and some viruses will exploit this by scanning random addresses looking for a computer that may be vulnerable to attack. Imagine someone walking down the street, knocking on the door of one house after another, and if no-one answers, checking to see if the house is unlocked.  Except on the Internet it’s possible to check thousands of houses (computers) in seconds.

What a firewall does is to inspect traffic coming into your computer and checks to see if it was something you asked for, such as a web page or an email. If this data was not requested by your computer it will ignore and block it, pretending as if there was no computer connected at all.

There are two main types of firewalls, hardware and software. Hardware means a separate piece of equipment between your computer and the Internet. The most common type is a “router” which will sometimes be found as part of a more expensive broadband modem. These are very good at stopping unwanted incoming attacks. Anyone purchasing broadband should consider paying a little extra for a modem/router combination, which includes firewall protection.

A software firewall is a program that runs on your computer and is also very good at protecting you – in fact it can protect you in more ways than a typical hardware one. It can do this by also stopping all outgoing Internet access unless you specifically allow it. So for instance if a virus tried to send itself out to other people without your knowledge it would stop it and alert you to the danger. It’s also handy for stopping some programs from automatically connecting to the Internet, especially if you are unsure what the program does. Even more beneficial, it can effectively block infections by spyware and other malicious programs that wish to take control of your computer. The downside is that as a program, it needs to be running all the time to be effective. They also require each program that uses the Internet to be added to the list of “allowed” programs. There are many available, but my personal favourite is ZoneAlarm from Zone Labs who offer a free version at www.zonelabs.com.

Windows XP comes with a basic software firewall, and the recent release of Service Pack 2 (SP2) has added more strength and security features. As well, some anti-virus products also include extra security and firewall protection. It is a good idea to run both a hardware and software firewall to give the best protection.

All these things can help you enjoy the Internet without the danger and hassles that come with your computer being attacked from outsiders. Personally I wouldn’t be without any of them.