"By now, most people in the Linux world have heard of Security Enhanced Linux (SELinux). Since its initial release by the National Security Agency in 1999, SELinux has become a standard part of the Linux kernel and a supported capability in many Linux distributions including Red Hat Enterprise Linux 4 and 5.
"What you may not realize is all the ways SELinux is being applied to a variety of security challenges. Just because SELinux was initially developed by the military does not mean it is only useful to complicated security problems and large-budget organizations--SELinux is for you too. And despite what you might have heard, you don't need to be an expert to reap the benefits of SELinux's powerful protection features..."