IPv6 is enabled by default in Ubuntu. But you may want to disable IPv6 for many reasons. Some programs may cause problems when IPv6 is enabled, So if you are not planning to use IPv6, simply disable it and not worry about any potential problems. In this tutorial we will learn you how to disable IPv6 on Ubuntu 18.04 LTS.
This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo’ to the commands to get root privileges. I will show you through the step by step disable IPv6 on an Ubuntu 18.04 Bionic Beaver server.
Step 1. First, make sure that all your system packages are up-to-date
sudo apt update sudo apt upgrade
Step 2. Permanently Disable with sysctl.
To disable IPv6 using sysctl, Open the Ubuntu terminal and Perform the following steps:
nano /etc/sysctl.conf
Add the following lines at the end of the sysctl.conf file:
net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.lo.disable_ipv6 = 1
In Ubuntu server 18.04 LTS, you will need to add additional lines for each interface you want to disable IPv6:
net.ipv6.conf.<ifname>.disable_ipv6 = 1
For change to be effected, run the sysctl -p command:
sysctl -p
Step 3. Disable IPv6 using GRUB.
Perform the following steps with root privileges
Open the /etc/default/grub, Modify GRUB_CMDLINE_LINUX and GRUB_CMDLINE_LINUX_DEFAULT to append ipv6.disable=1:
GRUB_CMDLINE_LINUX="ipv6.disable=1" GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"
Update the grub configuration:
update-grub
update-grub
Reboot the server:
systemctl reboot
Congratulation’s! You have successfully disable IPv6. Thanks for using this tutorial for disable IPv6 on your Ubuntu 18.04 Bionic Beaver system. For additional help or useful information, we recommend you to check the official UFW Firewall website.