Security-Enhanced Linux (SELinux) is a Linux feature that provides a mechanism for supporting access control security policies, including United States Department of Defense-style mandatory access controls, through the use of Linux Security Modules (LSM) in the Linux kernel. It is not a Linux distribution, but rather a set of Kernel modifications and user-space tools that can be added to various Linux distributions. Its architecture strives to separate enforcement of security decisions from the security policy itself and streamlines the volume of software charged with security policy enforcement.
But sometimes managing a SELinux is a big head ache.
Following is the way to disable the SELinux on you CentOS 6 installation
Open /etc/selinux/config with your favorite editor
Check for SELINUX=enforcing
This will disable SELinux on your next reboot.
To diable SELinux, without having to reboot, you can use the setenforce command like so: