RedHat / Centos Disable IPv6 Networking

Our policy and network configuration does not requires IPv6 support in RHEL / CentOS / Fedora Linux. How do I prevent the kernel module from loading at boot time and disable IPv6 networking?

You can easily prevent the kernel module from loading by updating the following two files:

1. /etc/modprobe.conf - Kernel driver configuration file.
2. /etc/sysconfig/network - RHEL / CentOS networking configuration file.

/etc/modprobe.conf

Edit /etc/modprobe.conf, enter:
# vi /etc/modprobe.conf
Append the following line:

install ipv6 /bin/true

Save and close the file.

/etc/sysconfig/network

Edit /etc/sysconfig/network, enter:
# vi /etc/sysconfig/network
Update / add as follows:

 
NETWORKING_IPV6=no
IPV6INIT=no
 

Save and close the file. Restart networking service
# service network restart
# rmmod ipv6
Alternatively, simple reboot the box:
# reboot
Verify IPv6 is disabled, enter:
# lsmod | grep ipv6
# /sbin/ifconfig