I'm looking to permanently disable IPv6 on a specific interface because it's broken and my question on Superuser to fix it is dead so how can I go about doing that? I've added net.ipv6.conf.eth0.disable_ipv6=1 to /etc/sysctl.conf but it doesn't work for some reason. At the moment I just use the sysctl command every time I turn on my PC to disable it.

  • 2
    Do you see value in sysctl.conf persistent after reboo....you can also put up sysctl -w net.ipv6.conf.$IFACE.disable_ipv6=1 in the /etc/interface file Mar 14, 2015 at 18:25
  • @Miline if you're asking if the entry stays there after reboot yes it does.
    – Scoopta
    Mar 14, 2015 at 19:54
  • your problem is syntax in the sysctl.conf file you need to use the syntax net.ipv6.conf.eth0.disable_ipv6 = 1 instead of net.ipv6.conf.eth0.disable_ipv6=1
    – mchid
    Mar 14, 2015 at 20:28
  • @mchid does that space really matter?
    – Scoopta
    Mar 14, 2015 at 20:29
  • @Scoopta yes, I believe so. If you look at the default options in that file they all use the same syntax and I believe I've seen this issue before with setting swappiness.
    – mchid
    Mar 14, 2015 at 20:34

2 Answers 2


First, edit /etc/default/grub and find the line:


and change the line to say this instead (this will disable ipv6 completely):


alternatively, to leave the ipv6 stack functional but to disable assignment of ipv6 addresses you can use the following option instead:


Finally, run:

sudo update-grub

and reboot to apply the changes.

This will disable ipv6 at the kernel level so that it is never enabled from the get-go.

Also, after making the following changes to /etc/sysctl.conf

net.ipv6.conf.eth0.disable_ipv6 = 1

Run the following command to apply the changes:

sudo sysctl -p

Finally, if using the option to disable ipv6 in sysctl.conf, you need to also make sure ipv6 is commented out in /etc/hosts. See here https://wiki.archlinux.org/index.php/IPv6#Disable_functionality


Neither the grub nor the sysctl solution worked for me. My guess is that systemd reenabled ipv6 during boot.

So I changed systemd to only configure ipv4 for my en* devices:

sudo vim /etc/systemd/network/en-all.network

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