Raspberry Pi: disable IPv6

raspberry-disable-ipv6.md

Disabling IPv6

Source: https://www.leowkahman.com/2016/03/19/disable-ipv6-raspberry-raspbian/

Firstly, check for presence of IPv6 using ifconfig. You should be seeing a few lines containing inet6 addr: ....

To disable, edit a file: sudo nano /etc/sysctl.conf

Add the following line:

net.ipv6.conf.all.disable_ipv6 = 1

For the change to take effect without rebooting: sudo sysctl -p

Verify that IPv6 address does not show up in ifconfig.

If you wish to re-enable, change the value in the setting above from 1 to 0 then execute the following two lines:

sudo sysctl -p
sudo ifconfig eth0 down && sudo ifconfig eth0 up

If you are doing this over SSH, the current session will of course be cut off. You should be able to reconnect in just a few seconds.

This has worked fine on OS versions up to and including Bullseye, but for me it is NOT working on bootup on Bookworm.
Anyone found a fix ?

I have found a work around that I did not need to do on bullseye which is to add the following to /etc/rc.local
service procps reload

Fixed it with Network Manager on command line:

1. nmcli connection show
2. nmcli connection modify <connection_name> ipv6.method ignore ipv6.ip6-privacy 0 connection.autoconnect yes
3. reboot

This command sets IPv6 method to "ignore", sets IPv6 privacy to "0" (optional, but it ensures IPv6 privacy extensions are disabled), and sets the connection to autoconnect. This ensures that the IPv6 configuration remains disabled even after a reboot.

Thank you very much for this nugget of pure goodness. I've been down a bit of a rabbit-hole trying to eradicate IPv6 on some of my Raspberry Pi installs, and I'd already done the sysctl.conf stuff and also edited cmdline.txt and I was still seeing IPv6 entries when running an 'ip addr' query.

After applying your fix, I was overjoyed to see just IPv4 stuff. Many thanks @barci335

John G

After my post from Jan 2024, I found that adding 'ipv6.disable=1' to /boot/firmware/cmdline.txt also works

A potential problem with adding the settings via the Network Manager CLI is that if you use multiple network interfaces, i.e. different Wifi's depending where the device is used then you need to do that for each one.