If you need some boning up on OpenBSD — the secure, free, open source Unix-like operating system, No Starch (www.nostarch.com) has the book for you: “Absolute OpenBSD, 2nd Edition” by Michael W. Lewis.
The US$59.95, 536-page tome is a complete guide to OpenBSD, which is widely used as the basis for DNS servers, routers, firewalls, and more. This edition is completely updated to cover OpenBSD 5.3 and includes new coverage of OpenBSD’s boot system, security features like W^X and ProPolice, and advanced networking techniques.
Lucas is a network/security engineer and the author of “Absolute OpenBSD,” “Absolute FreeBSD,” “Network Flow Analysis,” “Cisco Routers for the Desperate,” and “PGP & GPG.” You can learn more about him at http://www.michaelwlucas.com/ .