This part of the book is directed primarily towards Unix system administrators. It describes how to configure Unix on your computer to minimize the chances of a break-in, as well as how to limit the opportunities for a nonprivileged user to gain superuser access.
Chapter 17, discusses strategies for downloading security patches and keeping your operating system up to date.
Chapter 18, discusses why and how to make archival backups of your storage. It includes discussions of backup strategies for different types of organizations.
Chapter 19, describes ways that an attacker might try to initially break into your computer system. By knowing these "doors" and closing them, you increase the security of your system.
Chapter 20, discusses how to monitor your filesystem for unauthorized changes. This chapter includes coverage of the use of message digests and read-only disks, and the configuration and use of the Tripwire utility.
Chapter 21, discusses the logging mechanisms that Unix provides to help you audit the usage and behavior of your system.