Using A Personal Firewall
Why It's Important
Many people who use the internet are not aware that other computers on the internet are able to detect the presence of their computer and are able to extract information about the computer and the person using it. In some cases they may be able to read documents on your computer, print to your printer or, even run a program on your computer without your permission. This is true regardless of how you connect to the internet (dial-up, DSL or Cable).
A firewall helps to prevent other computers on the internet from detecting the presence of your computer and will help prevent others from being able to access your computer from the internet without your permission. A firewall can also be set so that only programs on your computer, that you have authorized, are able to talk to the internet.
What You Can Do About It
Most suppliers of anti-virus programs also supply personal firewall programs. Often times anti-virus programs and personal firewall programs are sold together. Windows XP and Mac's have simple firewalls built into them. Alternatively, you can buy a firewall appliance that you connect between your DSL (or Cable) modem and your computer.