How to 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:

/etc/modprobe.conf - Kernel driver configuration file.

/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