This book sorts through the overwhelming mass of open source security tools, chooses a few of the best, and shows network and system administrators how to use them to solve common security problem. Open Source Security Tools is a practicum. It tells readers what they need to do to secure their networks, introduces best-in-class tools, and shows readers how to use them. For each security task described, Howlett reviews the best open source tools, shows readers how to use them, and takes them through a sample implementation and case studies. At the end of each chapter, Howlett will offer pointers to other good open source tools that are worth investigating. The companion CD includes fully dowloadable versions of the tools, so readers can work along with the text. Newcomers to security will leave with enough knowledge and experience to deploy solutions and further their IT careers. Readers will learn to: * Secure their perimeter with open source scanners like Nessus.* Receive early warning about attempted breakins from IDS systems like Snort.* Install a firewall to keep hackers at bay (Turtle).* Use encyrption to secure email and other sensitive data (PGP)* If the worst happens, run forensics tools to investigate a breakin after the fact, like Autopsy or SleuthKit.This book is part of the Bruce Perens Open Source Series.