Disable IPv6 on CentOS 6

To disable IPv6 on CentOS 6, run the following commands:

echo 'net.ipv6.conf.all.disable_ipv6 = 1' >> /etc/sysctl.conf
echo 'net.ipv6.conf.default.disable_ipv6 = 1' >> /etc/sysctl.conf
echo 'NETWORKING_IPV6=no' >> /etc/sysconfig/network