Disabling IPv6 address on Ubuntu 20.04 LTS Focal Fossa step by step instructions

Objective: To disable ipv6 where it is persistent among reboots

In case you need more permanent solution to disable IPv6 even after system reboot follow the steps below:

STEP 1:

As an administrative user open up the /etc/default/grub file using your favorite text editor and make to following changes:

FROM:
GRUB_CMDLINE_LINUX_DEFAULT=""
TO:
GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"

STEP 2:

Once ready update Grub menu:

$ sudo update-grub

In case you need to re-enable the IPv6 network addresses simply remove the ipv6.disable=1 from the /etc/default/grub file and run the update-grub command.