On Sun, Jan 11, 2026 at 4:58 AM Reinder <[email protected]> wrote: > > > > > At the moment I am thinking maybe ifup is still doing something? Though > > there is no inet6 configuration in /etc/network/interfaces: > > > It seems to be indeed an ifupdown issue, forcing a static ipv6 in > /etc/network/interfaces works, see below. > Problem is I did not want to do this. Will debug some more.
If I am not mistaken... If you are not using NetworkManager, and you are not using Systemd, and you are not using Kea, then you are probably using dhcpcd-base+ifupdown. Maybe there's something in dhcpcd-base that will provide the next path to go down. > root@reinder:~# sysctl -a | grep accept_ra\ > net.ipv6.conf.all.accept_ra = 0 > net.ipv6.conf.default.accept_ra = 0 > net.ipv6.conf.ens18.accept_ra = 0 > net.ipv6.conf.ens19.accept_ra = 1 > net.ipv6.conf.lo.accept_ra = 1 > root@reinder:~# sed 's#[0-9]*:*:*:*:*:#xx:xx:xx:xx:xx:#' > /etc/network/interfaces > # This file describes the network interfaces available on your system > # and how to activate them. For more information, see interfaces(5). > > source /etc/network/interfaces.d/* > > # The loopback network interface > auto lo > iface lo inet loopback > > # The primary network interface > allow-hotplug ens18 > iface ens18 inet dhcp > iface ens18 inet6 static > address xx:xx:xx:xx:xx:7b8:627:2::d59a:fd8c/64 > autoconf 0 > accept_ra 0 > > # The secondary network interface > allow-hotplug ens19 > iface ens19 inet dhcp > root@reinder:~# ip a s dev ens18|grep kernel_ra|sed > 's#[0-9]*:*:*:*:*:#xx:xx:xx:xx:xx:#' > root@reinder:~# >
