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Disable IPv6 on Ubuntu Server Permanently

Disable IPv6 on Ubuntu Server Permanently

To check the settings on the server install:

sudo apt install net-tools 

And run:

netstat -tnl

In a situation where ipv6 is not turned off, you should get something similar...

Disable procedure ipv6:

First edit:

sudo nano /etc/default/grub

by changing the following lines:

GRUB_CMDLINE_LINUX_DEFAULT=""
GRUB_CMDLINE_LINUX=""

They will change them to:

GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1"
GRUB_CMDLINE_LINUX="ipv6.disable=1"

Next, run:

update-grub

The next step disabling IPv6 via sysctl settings
In order to make the above sysctl changes permanent.
The following file needs to be changed:

sudo nano /etc/sysctl.conf

Then add the content below in the file and save:

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

In order for everything to be as it should be, it is necessary to restart the server.

reboot

Method to Disable IPv6 on ARM Ubuntu Server 24.04 on Orange Pi ...

Blacklisting the IPv6 Kernel Module edit:

sudo nano /etc/modprobe.d/blacklist.conf

Add the following lines:

# Disable IPv6
blacklist ipv6

In order for everything to be as it should be, it is necessary to restart the server.

reboot

Enter the command again:

netstat -tnl

You should get something similar: