Chapter 4. Safety and Security

Keeping systems secure is a hot topic these days, with mainstream media reporting on viruses and security flaws affecting popular (and, unfortunately, widespread) software. As the administrator of a system, you are responsible for making sure that your system is as safe and secure as possible.

While a part of this entails keeping your software up-to-date to incorporate security fixes, you also need to disable dangerous services that might be active by default on your system. You'll need to make sure that you and your users have a good password that can't be easily broken.

Making regular backups improves the safety of your system. Even if your system is never cracked by nefarious people, you'll still probably suffer from a failed hard disk or a user accident ("I just deleted my home directory!") at some point. It's also a good idea to install a virus scanner to prevent viruses on other operating systems from passing through your email server to attack the machines pulling their email from your Unix system. This chapter will show you how to keep your network safe and secure.