Shows up in 16.04.5 (4.15.0-43-generic) too. In the end, despite all the above ipv6.disable = 1 additions to sysctl.conf and reboots, the only sure-fire way I found to reliably disable ipv6 was to add ipv6.disable=1 to grub:
$ grep ip /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="ipv6.disable=1 quiet splash" $ sudo update-grub $ sudo reboot -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1771222 Title: Using sysctl to permanently disable IPv6 doesn't have any effect Status in linux package in Ubuntu: Confirmed Bug description: Shows up in version 18.04 of Ubuntu. I added the following 2 lines in /etc/sysctl.d/99-sysctl.conf and /etc/sysctl.d/01-disable-ipv6.conf: ``` net.ipv6.conf.all.disable_ipv6=1 net.ipv6.conf.default.disable_ipv6=1 ``` Rebooting my machine sets those parameters for "all" and "default" but not for the sysctl options of my network interface: ``` net.ipv6.conf.all.disable_ipv6 = 1 net.ipv6.conf.default.disable_ipv6 = 1 net.ipv6.conf.ens160.disable_ipv6 = 0 ``` I use disable_ipv6 above as an example. I've also verified this with the promote_secondaries option of ipv4. I can always restart systemd-sysctl.service at every boot and this will set net.ipv6.conf.ens160.disable_ipv6 to 1. Unfortunately though this won't work for devices that are hot-plugged. Other info: - version signature: Ubuntu 4.15.0-20.21-generic 4.15.17 - lspci is attached To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1771222/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
