Tiny Personal Firewall
It's not called "Tiny" for nothing. The software occupies just 900 Kbytes of disk space when installed, and the whole installation package is just 1.3 Mbytes. But despite that small size, it's quite complete, as the company's Web site abundantly details in the features list and comparison chart.

The intro text also mentions two interesting facts: The Tiny Personal firewall is built to the same certification standards as are ZoneAlarm, Sygate, and the Norton Personal Firewall; the U.S. Air Force uses Tiny software, as part of its central management package, on some half-million desktop systems. That's a major win for any security product.

Oddly, for a firewall that communicates so well with a central management suite, it's not as communicative with the desktop user. This may not be an issue if you just want the firewall to do its thing, without worrying about the details. But it may frustrate users who want finer control or greater feedback. Tiny does offer rule-creation and editing, and a few advanced features in the basic firewall program. But users have to run a separate "PFWADMIN" tool to access connections statistics, logs, and such. And even then, the amount of information provided isn't as much as with the other firewalls in this roundup. That's part of the tradeoff of being tiny; the basic features are all there, but some common bells and whistles have been omitted.

That may or may not matter to you. If not, Tiny firewall may be just the ticket.

The Tiny Firewall is free for personal use or $40 for a single commercial seat, with quantity discounts available.

ZoneAlarm
ZoneAlarm, in many ways the de facto gold standard of desktop firewalls, is in mixed versions: The $50 pro firewall has evolved to version 3, while the basic firewall (free for personal use or $20 otherwise) is still in version 2. You can see the differences between the versions here.

As a longtime user and fan of ZoneAlarm Pro--it's really an excellent tool--I'd looked forward to the release of version 3. But I have to say I was initially disappointed. It's slower and more porcine than its predecessor, and some of the new "features" are a major headache.

In its zeal to protect users from all manner of Internet nasties, the folks at ZoneLabs gave the new version the ability to block cookies, ads, and "mobile code" (meaning scripts, embedded objects, and such). The concept is fine, but it works too well. When you engage the new features at high security levels, only the most-plain-vanilla Web pages work.

That's annoying as a Web user, and it's horrible as a site owner. As soon as ZoneAlarm Pro 3 came out, I immediately saw an increase in customer-support issues from the Web sites I manage. Many ZoneAlarm Pro 3 users could no longer log on to password-protected pages. They couldn't use script-based Web forms. And they couldn't even download harmless software that was offered by a redirection link embedded within a page (to start a download automatically, several seconds after the visitor reaches the page).

I also saw a noticeable drop in banner-ad revenue, which I assume was from as ZoneAlarm Pro 3's preventing the normal display of ads. And, while this may sound like a petty thing, the fact is that without ad revenue to support them, there's no way for free sites to stay alive. So it's ironic. ZoneAlarm Pro 3 may improve your security because you'll have fewer sites to connect to and because you can't do much of anything on the sites that are there.

It seems to me that the folks at ZoneLabs simply went too far this time and developed a good product past its optimum level. Fortunately, ZoneLabs is hastily amending its code and already has issued a number of software updates. Plus, you can simply turn off the over-the-top "privacy" security features. I've done so and recommend you do, too, if you're using ZoneAlarm Pro 3. Even with them off, the rest of ZoneAlarm Pro 3 affords an extremely high level of security, easily the equal of other firewalls.

Other improvements in the new pro version are welcome. The built-in log viewer and analysis tool, for instance, lets you accomplish in one step what used to take several steps using third-party tools.

The basic version of ZoneAlarm lacks the overly aggressive privacy features and lets most Web sites operate normally. Although it lacks features such as the built-in log analyzer, its lower cost may make it a better deal than the pro version.