Protecting Your Computer with a Firewall

Windows computers can be attacked in many ways — and not just with viruses, worms, or Trojan horses. Another popular way to attack a Windows computer is to attempt to communicate to it over any of the network “ports” found on Windows computers. These ports are kind of like TV channels or radio frequencies: Computers are set up to listen for messages that may arrive from other computers — this is how they communicate with one another.

How firewalls work

Firewalls monitor all the communication between your computer and the Internet. Firewalls know what kinds of communication are allowed to flow in and out. They know this because they have something called an “access control list” — a list of rules that specify precisely what kinds of communications are allowed and what kinds are blocked. The firewalls made for the consumer market (that’s us) are usually preconfigured to offer maximum protection right out of the box.

The configuration required to facilitate communication between two computers in a home network makes them highly vulnerable to attack from any computer on the Internet. (Sinister music begins to play; the camera zooms in. . . .)

To turn your computer into a tattletale zombie, all anyone on the Internet needs to do is send a specially tailored message from their computer to one of yours — over one of the open ports.

Whether the firewall is a hardware device connected to your network, or a software program in your computer, a firewall will automatically block all unwanted network communication from the Internet, while at the same time permitting any legitimate communication that you need to use your computer.

Software firewalls

A software firewall is a program that runs inside your computer and blocks unwanted network traffic. Software firewalls are a necessity for any laptop computer, especially one that connects to the Internet from a variety of locations. Wherever your laptop goes, so too goes your fire- wall, because it’s right there inside. But if you have a desktop computer and you connect to the Internet using a dial-up modem, you’ve got to get a software firewall to protect it.

Sometimes software firewalls are known as personal firewalls, so named because they are your very own.

Purchasing software firewalls
If you’re in the market for antivirus software, or would consider upgrading or switching brands, then I suggest you give all-in-one PC security products serious consideration. Some companies with such offerings include:

  •  Norton Internet Security from Symantec: Included in this bundle are antivirus, firewall, privacy control, antispam, and parental control. www.symantec.com
  •  Internet Security Suite from McAfee: This bundle includes antivirus, firewall, antispam, and privacy control. www.mcafee.com
  •  PC-Cillin Internet Security from Trend Micro: This includes antivirus for your PC and for your PDA, spam filtering, privacy protection, and antispyware. www.trendmicro.com

 

Using software firewalls

When they are configured correctly, there is little — if anything — to do on a software firewall. If you’re using a software firewall that asks you whether the so-and-so program should be permitted to access the Internet, you’ll still see these messages from time to time.

In most cases, you need never look at the logs in which the entries for blocked communications are kept. You’re hiring the firewall to keep everyone out, but not necessarily to tell you who they all are.


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