Learn techniques for making your Linux system more resistant to attacks, including securing the boot process and local filesystems, locking up services and daemons, enforcing quotas and limits, enabling mandatory access control, and recognizing security vulnerabilities that can be introduced when updating security with new software. Part 1 in this series introduces security concepts and potential threats. Part 2 lists the concerns to keep in mind when planning a secure installation.
http://www-128.ibm.com/developerworks/linux/library/l-seclnx3/?ca=dgr-lnxw99SecLinP3