Using a Good Firewall

Firewalls gobble up precious system resources, especially on older computers and operating systems, so I wouldn't recommend one if it wasn't a necessity. Once upon a time, there was a debate over whether a firewall was necessary if you connected to the Internet using a dial-up connection. However, crackers and data thieves randomly barrage PCs connected to the Internet with pings and port scans , probing for unprotected systems. Once such a system is found, a cracker can compromise it with a Trojan horse, spyware, or a malicious worm. The bottom line is that any personal computer connected to the Internet is a potential target. My computer, with its broadband connection, is accessed hundreds of times a day by hackers, spies, and corporate snoops probing my computer for vulnerabilities. Each alert in the ZoneAlarm log shown in Figure 12.26 is an example of an unwelcome intruder!

Even if you only use a dial-up connection an hour a day, your computer is vulnerable. Your only viable option is to use a firewall for protection. Windows XP comes with a built-in bare-bones firewall, but I don't recommend it. I suggest you install the free version of ZoneAlarm instead. I use ZoneAlarm Pro, which also blocks cookies and pop-up ads. I consider it the most bulletproof firewall available. Follow the prompts to download a free version at http://www.zonelabs.com.

Note  

Be sure to disable XP's built-in firewall prior to installing ZoneAlarm.

To disable Windows XP's built-in firewall

1. Open the Control Panel.

2. Click on Network and Internet Connections

2. Click on Network Connections.

3. Right-click on each Internet connection (including dial-up, LAN, or high-speed).

4. Select Properties.

5. Click the Advanced tab.

6. Uncheck the box in the Internet Connection Firewall section.

Unlike an antivirus or spyware detection, which must be activated to scan your system, a firewall is pretty much "set it and forget it." Once installed, the firewall keeps your personal data and privacy safe from hackers and data thieves, and protects your PC from intrusion and attack. By blocking the ports of your computer, a firewall makes your machine invisible to other computers on the Internet. If you can't be seen, you can't be attacked ! That's the principle behind practicing stealth (Chapter 3).

Figure 12.29: The Internet Connection Firewall dialog box