Comment 9 for bug 1627641

I understand this better now. networkd actually went to handling DHCPv6/RA in userspace (https://github.com/systemd/systemd/commit/3b015d40c19) so that it actually *can* wait for IPv6 RA addresses -- if the kernel handles them, it does not know what to expect.

In yakkety we let networkd do that, but in xenial we revert it (https://anonscm.debian.org/cgit/pkg-systemd/systemd.git/tree/debian/patches/Revert-Revert-networkd-ndisc-revert-to-letting-the-k.patch?h=ubuntu-xenial) as networkd v229 has some regressions wrt. IPv6 handling compared to the kernel. These are fixed in 231, so we could drop the Debian reversion patch and instead backport these fixes.

nplan and wait-online works fine with the patch dropped, for the record.