h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The 'Is There Anyone Out There' forum has generated some interest in securing a unix system.
Any and all comments about it please

Here's a couple of things to start with.

Turn off all non essential services (apache, bind, ftp etc).
Make sure those services that can see the outside world don't run as root (most have an option to run as a less priveliged user).

A word of warning about mandrake linux 7.0.
If you try to install it at its most secure setting, then it asks you for a pasword twice, and when it reboots, the only way to recover from it is to reinstall at a lower security setting. I know, I found it out the hard way.