Security Enhanced Linux (SELinux) is a security enhancement to Linux implementing mandatory access control (MAC). Users and processes can be granted their least required privileges in a much more granular way than with traditional Unix access control. For example, you can define a policy to prevent your web browser from reading your SSH keys. The security model of SELinux has been ported to other operating systems; see SEBSD for FreeBSD and Project fmac for OpenSolaris.
For downloads and more information,
visit the SELinux homepage.
"selinux"is ultimate in security. it was develoved by NSA & it makes your servers almost unhackable. it can offer you military grade security. in future it is going to be among top 3 security tools. only problem with this is difficult to understand syntax.
basically it adds another layer of security to linux. "REDHAT" is doing lot on this technology to make it simple to learn.