Proton VPN now offers an official Linux app with graphical user interface and an official Linux CLI. Both these clients have built-in IPv6 leak protection, with no user configuration required.

We recommend using our official Proton VPN apps on Linux. However, it is also possible to manually configure a VPN connection in Linux using the  OpenVPN or IKEv2 VPN protocols.

If using a manual VPN connection, we recommend disabling IPv6. The following solution should work for most Debian-based distros.

1) Open Terminal and enter the command:

sudo nano /etc/sysctl.conf

2) Add all the lines to the bottom of the file and save it:

net.ipv6.conf.all.disable_ipv6 = 1 
net.ipv6.conf.default.disable_ipv6 = 1 
net.ipv6.conf.lo.disable_ipv6 = 1 
net.ipv6.conf.tun0.disable_ipv6 = 1

3) Now make the system read the file and confirm the changes using this line:

sudo sysctl -p

That’s it! In order to check whether IPv6 was disabled on your computer, you can do an IPv6 leak test here.

Related articles:

How to use Proton VPN on Linux
How to disable IPv6 on Windows
How to disable IPv6 on macOS