"Objectives
After completing this tutorial, you will know basic concepts in
security administration, including how to secure Secure Shell (SSH)
remote logins, create firewall rules, and watch logs for possible
attacks.
"Prerequisites
This tutorial is written for the beginning GNU/Linux user. You
should have some familiarity with operating system installations
and the command line. To fully understand the concepts in this
tutorial, you should have gone through the companion tutorial,
"Hardening the Linux desktop."" Free registration required--ed.