Firewalls, like nearly all security-related technologies, come in a variety of shapes, sizes, and price ranges. You can certainly purchase a hardware-based firewall for a few hundred dollars. A hardware firewall is a small device that you place between your Internet connection and your home computers. It is usually good to go this route if you have the budget or have several computers-often the case for people who maintain a home office. The hardware-based firewall will block unauthorized attempts to access your computers.

Another route to consider is replacing the piece of hardware that connects your home computers to your DSL or cable modem connection. Most newer connection devices (e.g., routers) used in always-on connections now come with built-in firewalls. For example, DLink Systems offers several devices for DSL and Cable Modem connections that include built-in firewall technology. Prices range from $80 to around $120.

However, for most home computer users, it is not necessary to go out and spend $100 or more to protect your systems. If you're budget minded you can still protect your home computers by installing and maintaining a personal firewall (along with antivirus software, of course).

A personal firewall is a piece of software that blocks unauthorized access to your systems. In addition, it can also usually inform you if software on your system is trying to phone home--a practice routinely performed by companies who want to gather information about you and your activity on the Internet.

Windows with walls

Undoubtedly, the best personal firewall for Windows-based computers has to be ZoneAlarm from Zone Labs. The company offers its base product (ZoneAlarm) as a free download for personal use. But it's worth the $49 for ZoneAlarm Pro, a personal firewall with other security measures included.

Aside from easy setup and configuration, and prevention of unauthorized inbound and outbound connections, ZoneAlarm Pro includes e-mail scanning and protection, intrusion blocking, hacker tracking, cookie management, ad blocking, and pop-up blocking. The combination of all these tools is a winner for security and for privacy.

Close on the heels of ZoneAlarm is SyGate's Personal FireWall, which is free for home use. The company also offers a Pro version of its personal firewall, which includes intrusion detection and product updates over time. Personal FireWall Pro costs $39, and a good level of support is available.

Another option to consider is BlackIce PC Protection from Internet Security Systems. It is not the easiest personal firewall to configure, and its screens are cluttered. BlackIce provides pop-up alerts when unauthorized access occurs, but the messages can be confusing for PC users who are not technically inclined.

Network Associates' McAfee division also offers Personal Firewall, which works very well, but operates somewhat differently than the other products: It is purchased on a subscription basis annually. The Personal Firewall does a fine job, but its interfaces are not the easiest to work with and it is probably not well suited to casual PC users.

Withstanding Mac attacks

Macintosh users have plenty of choices for personal firewalls, too. None of the Macintosh personal firewalls I examined are free, but there are trial versions available for all of them and the purchase prices are relatively low. And if you like, you can just use the built-in firewall that comes with the Macintosh operating system.

Pliris's Firewall X2 is a really well put together personal firewall. Easy to install and configure, it does not conflict with the built-in Macintosh firewall. What it does do is block unauthorized incoming and outgoing connections. It can notify you in real time when unwanted activity is taking place, and it offers fairly detailed logging.

The Impasse personal firewall from Glucose Development also does a fine job of blocking unwanted connections. For those who know they need a firewall but don't want to muck around with configuration, Impasse offers an easy mode setting with which you merely select applications that should and shouldn't be allowed inbound or outbound access. You can also get at the advanced options to closely set every aspect of communication.

Sustainable Softworks IPNetSentry is very easy to install and use; you don't need to spend tons of time setting options or configuring things. IPNetSentry sits quietly in the background and blocks unwanted activity. This is a good choice for the home user who wants firewall protection for his Macintosh, but doesn't have the time to goof around with settings and the like.

NetBarrier by Intego is a little pricier than the other solutions available for Macintosh. However, it includes more than just a personal firewall. The personal firewall portion of NetBarrier works as well as competing solutions. It prevents both inbound and outbound unauthorized access. Configuring it is a snap, and it includes a customized mode that lets you add your own firewalls rules. NetBarrier also includes intrusion detection capabilities, data filtering, and controls to help you manage cookies and block ads or spam. If you have the money to spend, this personal firewall is worth the price.

Linux protection

Most Linux distributions, such as SuSE and Red Hat, already come with a built-in personal firewall. And you don't have to be a geek to configure it. Several of them include graphical-based tools that make the setup a breeze. For example, SuSE's YAST Control Center enables users to configure the built-in firewall in just a couple of minutes.

If you use a Linux distribution that doesn't have a firewall, or you just want to use a different firewall than the one that comes with the distribution, there are a number of choices. FrazierWall, created by Ken Frazier, is one such option. This may not be a good choice for home users who have just made the switch to Linux, however. It is not as user-friendly as some other options, but a great choice for those who are a bit more technical.

The NetMax Firewall is a little spendy for many budgets, but the price includes a good level of support. What is most interesting about NetMax is that it includes a graphical interface to support firewall configuration, the firewall itself, and a full Linux distribution based on Red Hat's Linux distribution. This is a good choice if you want to install Linux with security in mind from the start.

SecurePoint offers home users a freeware version of the firewall it also sells to businesses. The SecurePoint firewall is a solid choice, but it does not include e-mail or phone support. Still, it is easy to set up and use. If you do want support, you might consider the business version of SecurePoint, which starts at $49.

Sentry Firewall CD takes an interesting approach to firewall technology. Sentry offers a free firewall, which is a Linux-based bootable CD-ROM. For the gearheads among us, this is a nice solution. Download it and give it a test drive. However, if you're new to Linux, this is not the most ideal personal firewall solution.