Provides techniques and advice for running three representative versions of the Linux operating system: Red Hat 7.2, SuSE 7.3, and Debian 3.0. The guide identifies the different pieces that comprise the major administrative systems and how they work together, and summarizes how to perform common procedures, such as adding and removing users, performing backups, and auditing security. Large sections are devoted to the domain name system configuration and the sendmail configuration.