Not so fast! What have you done to protect yourself from hackers and others who would like to use your computer without your knowing? We're not talking about other members of your family or employees, we're talking about users from the other end of the cable that brings the Internet into your home or office.

You most likely have an anti-virus program that came with your computer, as many come with them preinstalled, or 'bundled.' But this is not enough! Nowadays, you also need a piece of software called a firewall.

"What is a firewall?", you ask. A firewall is software you load onto your computer that allows you to control access from outside network resources, that is, other computers that are connected to the Internet.

It doesn't matter what kind of connection you use to connect to the Internet—dial-up modem, DSL or cable modem. All users should use a firewall. There are many people who will tell you that dial-up users do not need a firewall. You are at less risk, but at risk nonetheless! Your data is just as vulnerable on a dial-up connection as it is using any other type of connection to the Internet.

There are many different firewall programs available. Some are free and others require the purchase of a license to use the firewall software.

The biggest reason to protect your computer from outside intrusion is that you could have personal information on it, which could be very valuable in the hands of the wrong people.

Online banking and shopping information, personal medical profiles, professional correspondence and many other types of data can assist Internet criminals in emptying your bank accounts, destroying your credit rating and, in some rare cases, even lead to stalking and murder.

Using a firewall allows you to control who accesses your computer from the outside as well as giving you the "last word" in allowing other software you run to access the Internet.

There are many shareware and freeware programs that, while very useful, collect data and attempt to "phone home" in order to feed massive marketing databases used to target customers. These "spyware" programs send your personal data out of your computer without your knowledge or consent. Using a firewall helps you control the unauthorized use of your personal data.

There are several very good firewall products available to you for download from the Internet or for purchase at your local retailer.

I usually recommend either Black–ICE Defender from Network ICE or ZoneAlarm from Zone Labs depending upon the type of protection needed for your situation. Both are very good products and each has its own pros and cons. If you would like to find out more about these products, visit the Web sites and read about what they do prior to making your decision. In some cases, I recommend the use of both products.

Depending upon which firewall product you use, it will also protect you from certain e-mail viruses and trojans. A trojan is a piece of software that is designed to provide some useful functionality to the user but has other hidden functionalities that are usually used to intercept data or even allow someone complete control of your machine.

You may have heard of the Sub-Seven, Netbus or BioNet trojans which allow outside users to take over your computer, delete files, modify Windows settings, steal information, log keystrokes for obtaining passwords, and all kinds of other nefarious activity.

Now that you have your firewall installed, what next? The purpose of the firewall is to protect your computer, and in the course of providing that protection, it can capture and log a lot of data about the traffic that is coming to and from your computer.

Unfortunately, one of the weaknesses of the many firewall products on the market is a lack of ability in producing meaningful reports or allowing access to the data in a manner that makes it easy to understand. This is why we created our firewall log analysis tools.

ClearZone for ZoneAlarm and ClearICE for BlacklCE Defender enable you to easily obtain information from the firewall log data. Using this knowledge, you can determine the level of threat that you have been exposed to and take action to strengthen your security, or report the intrusion attempts to the proper authority, the intruder's ISP.

Depending upon the type or severity of the intrusion attempts, you can have the intruder removed from their Internet account. This would effectively keep them from attacking your computer. You can also print hardcopy reports of the intrusion attempts and graph the data to look for any trends that might indicate a weakness in your computer security efforts.

Ben E. Brady, of Brady & Associates, LLC, has been programming and developing custom database applications for more than 30 years, specializing in the reporting of data to make it easier to understand for end-users. He is a member of the Fresno PC Users Group, from whose newsletter this article has been reprinted.