SELinux is a Linux kernel addition and userland toolset used to provide mandatory access controls between subjects ( users & processes ) and objects ( files, devices ). SELinux has been adopted into the Linux 2.6 kernel, and will feature in the upcoming Fedora Core 2 Linux distribution. SELinux is avaliable for most LinuxDistributions, but most require additional work.

The project is guided by the NSA, the American National Security Agency.

Generally speaking, SELinux is not an option for the home or casual user, unless security is the sole reason you're migrating to Linux, it's unlikely to be suitable for your first install.

SELinux Resources:

NSA SELinux home page http://www.nsa.gov/selinux

Kerry Thompson's Unofficial FAQ http://www.crypt.gen.nz/selinux/faq.html

Kerry Thompson's SELinux resources http://www.crypt.gen.nz/selinux/links.html

Faye Coker's Getting Started HOWTO for Debian and Fedora http://www.lurking-grue.org/gettingstarted_newselinuxHOWTO.html

Russell Coker's SELinux resources http://www.coker.com.au/selinux

Tom Vogt's SELinux 2.6 kernel installation guide http://selinux.lemuria.org/install-2.6.html