From Bastille Man page:
Bastille Linux is a security hardening program for Mandrake, Red Hat, and Debian GNU/Linux. If run in the preferred Interactive mode (using InteractiveBastille), it can teach you a good deal about security while enhancing your system’s protection against attacks. If run in the quicker Automated mode (using AutomatedBastille), it can quickly tighten your machine, but not nearly as effectively (since user/sysadmin education is an important step!)
Bastille offers different security profiles which can be selected using BastilleChooser. However, note that even if servers and workstations have very different security levels, general security levels are not as good as security levels adapted to your own security policy.
Bastille can secure a number of hosts easily by defining a general configuration file and running BastilleBackEnd on each host individually. All security measures defined will be implemented (if possible) on all of them. Bastille changes can also be undone by using the RevertBastille command.