"We're not a security guard company. We sell a *concept* of security."-- Michael Kaye, president of Westec, a residential security company.

Title: Secrets of Computer Espionage: Tactics and CountermeasuresAuthor: Joel McNamaraISBN: 0-7645-3710-5Publisher: Wiley

Title: Linux Security CookbookAuthors: Daniel J. Barrett, Richard Silverman and Robert G. ByrnesISBN: 0-596-00391-9Publisher: O'Reilly

As I sat one morning working on some loose ends, my e-mail inbox signaled the arrival of some new message. Experience is the best teacher, and my experience told me this was a new worm or virus.

The attachment was zipped, so I saved it to my Windows desktop and then FTPed it to one of my Linux boxes. Once there, I was safe to play with it the way a cat plays with a small mouse it caught. Such is the nature of security today. What I once loathed, I now treat as a daily component of handling information.

The security layer is not as static as other parts of the information infrastructure; it changes and evolves new countermeasures constantly. I don't try to keep up with everything, but I do pay attention. Two books have caught my attention, one because it is a cookbook for Linux security, a time saver, and the other because it covers other things I don't deal with, but having the knowledge helps one make connections. My third and more personal reason is I do not like being surprised. When you have enough bad experiences with security issues, you come to understand this.

Secrets of Computer Espionage is an informative--and if you're a geek--an entertaining book. My expectation was this book would point me to a number of security-oriented Web sites, which it does. But as the author explains, spying techniques and countermeasures also should explore concepts of what you should protect, risk analysis in making determinations and even who are potential spies.

It would be enough if all the book covers is computer security, but it goes beyond that to electronic devices such as faxes, shredders, cell phones, PDAs and MP3 players. Many of the listed Web sites have a Windows orientation, but it's not exclusive. Linux and UNIX are included in this party.

As I'm not a security or "spook" type, I give the topic the time slice I can afford to allocate to it so I can do what I need to do, but this book has pushed security and how I think about it to a different level. My advice is the next time you go to your local bookseller, locate a copy, buy a cup of coffee and spend some time with it. I bet you'll be hooked.

The Linux Security Cookbook is much more focused in its scope, concentrating on providing recipes that readers can put quickly into use. The book is ideal for a Linux sysadmin in a small shop, where he/she is all things to all users. This book is not the complete and final word on Linux security, and it doesn't try to be. Instead, it is a series of security HOWTOs aimed at helping a system administrator make the best use of their time.

In my job as a UNIX/Linux support engineer, I deal with a focused area (High Availability clusters) and often deal with sysadmins who have little or no experience with a problem they encounter. Many of them, especially from smaller shops, are apologetic about their ignorance on some topic of HA clustering. I dismiss this immediately and tell them that when I was a sysadmin it was the same for me. The important thing is not knowing all the information, but knowing where to find it.

A short summary of the topics covered in this book begins with Tripwire and moves on to topics such as iptable and ipchains, network access control, authentication control, testing and monitoring. This is not a book I would read for recreational purposes, but it is a book I would reach for when some security issue has raised a red flag or when I feel I need to be proactive on some issue.

Frank Conley is a UNIX support engineer for Hewlett-Packard. He has been working and playing with Linux since 1995 and welcomes your comments.