Sometimes you will want to disable IPv6, in this article we will describe how to easily disable it.

Start by logging into your server as root user.

1. Edit /etc/sysctl.d/99-sysctl.conf (vim /etc/sysctl.d/99-sysctl.conf or nano /etc/sysctl.d/99-sysctl.conf)

2. Add the following lines to the end of the file:

net.ipv6.conf.all.disable_ipv6 = 1

net.ipv6.conf.default.disable_ipv6 = 1

net.ipv6.conf.lo.disable_ipv6 = 1

3. Save and exit the file

4. Reload the values

$ sysctl -p

5. Validate that IPv6 is disabled by running this command:

$ ip a

You should not see any 'inet6' lines anymore.

To verify this has worked reboot your server and run the last command again to see if it completely came through.