Question

How do I disable ipv6 on Ubuntu 20.04

I have followed every guide to disable ipv6 and yet after EVERY reboot I am still seeing it enabled. How do I disable it?

net.ipv6.conf.eth0.disable_ipv6 = 0

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Accepted Answer

Looks like /etc/default/grub.d/50-cloudimg-settings.cfg overrides the GRUB_CMDLINE_LINUX_DEFAULT="console=tty1 console=ttyS0 ipv6.disable=1" line. So set it in that file and then run update-grub.

nano /etc/sysctl.conf

Then add this line to this file:

net.ipv6.conf.all.disable_ipv6 = 1

Then run:

sysctl -p

That’s all :)

I put the following in /etc/sysctl.conf:

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