How to Disable IPv6 on Linux

How to Disable IPv6 on Linux

This tutorial explains how to disable IPv6 on Linux operating systems

Disabling IPv6 Temporarily

Open the terminal and enter these commands as super user:

sudo sysctl -w net.ipv6.conf.all.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.default.disable_ipv6=1
sudo sysctl -w net.ipv6.conf.lo.disable_ipv6=1

To verify if the IPv6 is disabled, run the following command. If its output is 1, that means the IPv6 has been successfully disabled. While the output 0 means it is enabled.

cat /proc/sys/net/ipv6/conf/all/disable_ipv6

Note: With this method, IPv6 will only be temporarily disabled. The next time you reboot, it will be enabled again.

Disabling IPv6 Permanently

Step #1: Edit the sysctl.conf file by running the following command as a super user:

sudo nano /etc/sysctl.conf

Note: If it says that “nano command not found”, then install it by running sudo apt install nano or sudo yum install nano according to the Linux distro in use.

Step #2: Now add the following lines at the bottom.

net.ipv6.conf.all.disable_ipv6=1
net.ipv6.conf.default.disable_ipv6=1
net.ipv6.conf.lo.disable_ipv6=1

Step #3: Save the changes by pressing Ctrl+O and return to the terminal by pressing Ctrl+X.

Step #4: Now enter the following command on the terminal for the changes to take effect:

sudo sysctl -p

To re-enable the IPv6, edit the systcl.conf again (Step 1), and remove the lines which you added in Step #2. Then save the file.

To check the IPv6 status, run the following command. If its output is 1, IPv6 is disabled. While the output 0 means it is enabled.

cat /proc/sys/net/ipv6/conf/all/disable_ipv6