The word 'firewall' referred originally to a physical barrier, usually a tall wall erected to contain the spread of fire. But the word is used most frequently nowadays in relation to computer security. A firewall is like the customs and immigrations: any data traffic entering or leaving your computer will be checked. There are two main types of firewalls for computers: hardware and software.

A hardware firewall is a physical component connecting your computer to the network or the internet. A cable/DSL router is a typical consumer-level hardware firewall. A router allows you to share your internet connection with other computers, by allowing you to connect many computers to the same internet connection. This is useful when you have a broadband, high-speed connection like the one on campus.

A software firewall is, obviously, software running on your computer that controls what data enters or leaves. It prevents unauthorized access to your computer from the internet, and allows you to control which programs can access the internet.

Q: Do I need a firewall?
Ans: Yes!

Your computer is vulnerable to hacking, because hackers can gain access through your computer through open ports. Hacks on the Internet commonly happen because of automated port scans by 'bots'(short for robots), software that scan the Internet for open ports. Hackers use the results of these scans to decide what to hack. An always-on connection will be picked up by an automated scan and will probably be broken into. If you have a dial-up connection, you are at a lesser risk because your time online is limited and you don't maintain a fixed IP address. With the broadband data connection on campus, you are at greater risk because you're always online and you're at a static IP address.

Q: What are the risks of not running a firewall?

Risk of virus and worm infection. The MSBlaster worm that shut down the Residential network in Fall 2003 is a good example. Worms spread between open, vulnerable computers in a network and a firewall is essential to slowing their spread.

Your data and personal information like credit card numbers may be stolen. Any information that you may store on your computer is at risk.

Your computer may be taken over. Programs can be installed and run without your permission. These programs can slow your computer, collect information about your internet usage, turn your computer into a server for illegal content or into a 'zombie' to attack other computers. And you may not even realize this is happening.

Q: So how do I install a firewall?

It is quite simple. You can buy firewall products from various companies, and some even offer a basic, free version for personal use. The list below shows some of the more popular ones. ZoneAlarm,and Sygate in particular, have a free version that is easy to use and simple to configure. Download the product from their website, and install it. It comes with a tutorial that explains how you can use it to improve the security of your computer.

Symantecs Personal Firewall
McAfee Personal Firewall
Zone Lab's Zone Alarm
BlackIce Defender
Sygate Personal Firewall
My Tiny Personal Firewall

BlackIce Defender and ZoneAlarm were two of the original Windows firewalls, and are still going strong. Norton Personal Firewall is also a mature product, and is the only personal firewall that also has a Macintosh version.