In the vast and varied universe of computer books, only a few stand out as the best in their subject areas. Building Internet Firewalls is one of those. It's deep, yet carefully focused, so that almost anything you might want to know about firewall strategies for protecting networks is here. In addition, there's lots of information on the reasons that we build firewalls in the first place, which is to say the security risks that come with Internet connectivity. You'll learn a great deal about Internet services and the protocols that provide them as you follow this book's recommendations for stifling attacks.

If there's a shortcoming to this book, it's its lack of coverage of the turnkey firewall products that are becoming popular among home and small-office users. Emphasis here is on more complicated network defenses that require careful design and setup — both design and implementation are the order of the day here. The authors carefully enumerate the threats they see in various situations, go into some detail on how those threats manifest themselves, and explain what configuration changes you can make to your perimeter defenses to repulse those threats. Plenty of illustrations make points about good and bad security strategies (you want to put the routers here and here, not here or here). You'll learn a lot by reading this book from cover to cover, no matter how much experience you have.