On Sat, Jan 10, 2026 at 11:30 AM Reinder <[email protected]> wrote: > > Hello Debian Users! > > Maybe I am doing something silly, but I am confused, so please educate > me if I am seeing/doing this wrong. > > When trying to disable automatic binding of a (wrongly) advertised ipv6 > IP I got stuck and only got it to work with the bottom two lines below > in my /etc/sysctl.d/am-no-ipv6.conf: > > root@reinder:~# cat /etc/sysctl.d/am-no-ipv6.conf > net.ipv6.conf.all.accept_ra=0 > net.ipv6.conf.all.autoconf=0 > net.ipv6.conf.default.accept_ra=0 > net.ipv6.conf.default.autoconf=0 > net.ipv6.conf.ens18.accept_ra=0 > net.ipv6.conf.ens19.accept_ra=0 > root@reinder:~# > > This is, to me, unexpected, even unwanted behavior? > I would expect disabling default and all to work and prevent ipv6 > routing and perhaps need of firewalling?!
Is the package linux-sysctl-defaults installed? See <https://www.debian.org/releases/trixie/release-notes/issues.html#etc-sysctl-conf-is-no-longer-honored>. Also, which version of Debian? > What I also tried before and still have access but does not prevent an > ipv6 from binding: > > root@reinder:~# tail -7 /etc/dhcpcd.conf > ## only ipv4 > ipv4only > ipv6ra_noautoconf > nodhcp6 > noipv6 > noipv6rs > noipv4ll > root@reinder:~# > > root@reinder:~# cat /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 > autoconf 0 > accept_ra 0 > > # The secondary network interface > allow-hotplug ens19 > iface ens19 inet dhcp > iface ens19 inet6 static > autoconf 0 > accept_ra 0 > root@reinder:~# Jeff
