Monday, July 09, 2007

Security for Me: Firewalls

Firewalls? What in the world are they? If you look up in Wikipedia you find: "A firewall is a hardware or software device which is configured to permit, deny or proxy data through a computer network which has different levels of trust." Huh? Of course... is something too complicated for you... or? No, it is not. And it is crucial for your computer.

To put it very simple, a firewall is a program that runs on your computer, or a piece of dedicated equipment, that does one thing only: protect your computer or home (or business, why not?) network from unauthorized and unwanted access, while in the same time gives you access to the Internet. It does that by intercepting the information received or sent by your computer before it can do any harm. Therefore, if a connection is not permitted, your computer will never even notice it (except the firewall software of course).

Windows and other operating systems come with built-in firewalls that nowadays are already turned on by the manufacturer. You should never disable it unless:

  1. you really know what you are doing (you are an expert or similar)
  2. your computer is protected by another firewall, like a DLS, ADSL, PPPoE or other broadband router that is recently manufactured and has an active firewall, or even another computer that is securing your network
  3. you are not connected to Internet in any way (it is an isolated network)

Even so, I don't recommend turning it off... never ever... Of course that I recommend to install a better security product that has a better firewall that the built-in one and I never recommend 2 active firewalls on the same machine as they can do more damage than prevent it.

Also, never attach a computer to a network and to the Internet unless the firewall is active.