This audience is comprised of engineers and administrators, who: 1. Protect their network and storage data from theft and/or corruption. 2. Ensure both Web-based and internal application and data availability to customers, business partners, and employees. 3. Optimize network hardware, software, storage, and bandwidth resources. The audience for this book includes the thousands of people who download Snort for the first time every day, as well as for anyone whou is familiar with the first edition of the book. They accomplish these tasks by installing, configuring, troubleshooting, and maintaining a combination of commercial and open source firewalls/VPNs, security appliances, Intrusion Detection Systems (IDSs), Packet Analyzers (Sniffers), and AntiVirus applications. This audience is task oriented and focused on executing IT objectives mandated by their ever-changing business needs.