What is a Firewall? The phrase comes from the automotive world. In a car, there is a heavy-duty wall of steel between you and the engine compartment. it divides the hot, hostile environment where the motor resides from the passenger compartment, protecting the passengers from the heat and fumes of the motor, and in extreme cases, from fire. The only things that are allowed to pass through it are things like electrical wires and control devices to operate the car. In a computer it can be a hardware or software solution that only allows those applications access to your computer to which you have previously given permission to do so.

   Although Wndows XP, Service Pack 2 has a built-in firewall, and it is better than nothing, it does not give you the ability to adjust the settings for individual applications or to examine what programs do have permission to access the Internet. There are other choices out there, but my favorite is ZoneAlarm from Zone Labs. It is effective, flexible, automatic, let's you know what's going on, and it's FREE!

The ZoneLabs website has lots of great information so be sure to place a bookmark (add to favorites) for their site. For now, you need to download the program. Click on The "Free ZoneAlarm and Trials" link on the main page. On the next page you will find the various products that Zone Labs present to you. You want to click on the "ZoneAlarm Free Download" link. Finally, on the last page, just click on the "Download FREE ZoneAlarm" link. The installation process is fairly self explanatory. During installation (and during subsequent updates) be sure to select the "Free" option. It is somewhat easy to miss if you don't examine the installation windows carefully! If you don't, it defaults to a trial of the Pro version and you will get pop-up remonders when the 30 day trial is about to expire, and you could have difficulties with ZoneAlarm after that. The Pro version does have a lot of nice features, though, so you may want to look into it on the ZoneAlarm website.

   Once you install Zone Alarm it pretty much takes care of itself. It will even check for updates on its own and will alert you if one is available. It even protects itself! If something tries to stop the application (such as when it turns itself off during an update) it asks if you really intended to do that! As you see above in the main interface, there are lots of tabs and buttons. To begin becomming familiar with how ZoneAlarm works, take the tutorial (indicated by the red arrow here). It will walk you though the workings of ZoneAlarm.

   When you first start the application you may wonder, "How do I give an application access?" Once you have connected to the Internet simply open any application that accesses your connection (E-Mail, Usenet, Internet, etc.), and Zone Alarm will add the application to it's application list that can be found on the "Programs" tab. At the same time the application attempts to access the Internet a pop-up box will alert you that some application has attempted access and it asks if you wish to give it permission. Above is a sample pop-up alert window. It is important to note that you should always look carefully at what the window says. if it is a program you you normall ues then there are two things you should do.

1) Here you see whee the alert tells you the aplication trying to access the Internet. In this case, it is firefox.exe, my browser. What if you don't know what it is? Use the Windows search function (Start/Search/Files or Folders) to search forthe location of the program on your hard drive.

2) The check box is to "Remember this setting." If the program at "1." If your selection in #3 below is the one you wish to use for this applciation all the time then select this check box now.Selecting this check box will also keep the alert for this program from popping up again.

3) Here you either "Allow" or "Deny" this program's access. If you checked the box in #2 above then this choice will be "permanent."

   Here is part of the window that appears on the "Programs" tab in the "Program Control" area. As you can see, each program that has tried for access has an entry (I have over 150 entries in mine!) How can you remember what they all are? You don't have to. Select one entry by clicking on it, and in a little window below the above interface you ge this:

As you can see, there is a good amount of information about the program. Of course, if it gets to the point that you have doubts about the programs in the ZoneAlarm program list, just delete those which are questionable (or just delete all the entries if you want) and start over, giving (or denying) the programs permission when they pop-up.

   The program entries are those that originally atempted access FROM your computer TO the outside world. If an outside application or website tries to access you computer other than the normal information uploads, Zone Alarm will stop them. With Zone Alarm working, ANY application that attempts to connect to the Internet will be stopped unless you have given it permission. The benefit of that is if a Trojan Horse attempts to send some information on your computer over your connection, it can be stopped unless you give it permission, so be careful about which applications you authorize.

   If at any time you think there is some suspicious activity going on using your Internet connection, Zone Alarm has a panic "Stop" button. Click on it and all activity going on through your Internet connection is immediately halted.

   After getting Zone Alarm working and adjusted, go back to my article. "Testing Your Computer's Vulnerability" and re-test your computer's security on the internet..    Be aware that Zone Alarm will not, nor is it meant to replace your virus protection software. Any virus or Trojan Horse that appears to be using approved applications (such as a worm that sends out your address book using your E-Mail application) will not be stopped by Zone Alarm, so you should still be suspicious of any attachments or executables that come your way.

   There is a lot of helpful information on the ZoneLabs website as well as the GRC website. The GRC site contains a lot of information on how the various systems on your computer communicate with each other and why the default setup is not a good one. It, of course, discusses how to change the settings for the best security level as well. Between the two you should have all your questions answered and all your security needs met.. For now.

   All of that protection, and Zone Alarm is free for personal use. What a deal!