Disable SELinux

SELinux is a security extension of CentOS that should provide extended security. 

Edit /etc/selinux/config and set SELINUX=disabled

vim /etc/selinux/config

# This file controls the state of SELinux on the system.

# SELINUX= can take one of these three values:

#     enforcing - SELinux security policy is enforced.

#     permissive - SELinux prints warnings instead of enforcing.

#     disabled - No SELinux policy is loaded.

SELINUX=disabled

# SELINUXTYPE= can take one of these two values:

#     targeted - Targeted processes are protected,

#     mls - Multi Level Security protection.

SELINUXTYPE=targeted

Afterwards we must reboot the system:

[ahmed@server ~]# reboot