Some distributions specialise in security issues (rather than, ease of installation, for example). If you are particularly concerned about security and cracking/hacking issues, these distributions are worth considering --- even if you don't install one, a review of their policies is educational.

Bastille Linux is of particular interest as it is a "secure" variant of RedHat Linux (the distribution supported by ISD at UMIST). Bastille consists of an automated set of security patches which are applied after a RedHat installation.

Bastille Linux

From the Bastille Linux web site: The Bastille Hardening System attempts to "harden" or "tighten" the Linux operating system. It currently supports Red Hat and Mandrake systems. We attempt to provide the most secure, yet usable, system possible.

EnGarde Secure Linux

EnGarde is a secure distribution of Linux that implements advanced security techniques. It can be used as a web, DNS, mail, database, e-commerce, and general Internet server.

Immunix OS

Immunix OS is a Linux distribution designed to be secure both now and in the future. The Immunix security tools (StackGuardT, SubDomainT, and CryptoMarkT) provide security bug tolerance so that even if security vulnerability is found in one of the programs supplied with Immunix, the vulnerability will probably not be exploitable by attackers. Immunix OS is based on Red Hat 6.2, but with all C source-available programs re-compiled with the StackGuard compiler. The result is a system that is fundamentally compatible with Red Hat Linux, but is secured against a majority of all Internet security attacks. It was developed as part of technology funded by DARPA --- U.S. Defense Advanced Research Projects Agency.

Trustix Secure Linux

Trustix Secure Linux is a project to make a hardened Linux distribution for servers. It features OpenSSL, OpenSSH, Apache w/SSL & PHP, Postfix, POP3 and IMAP with SSL support, ProFTP, and ftpd-BSD.