Comment 13 for bug 1771886

Lukas,

Thank you!

For the benefit of others, the drop-in file must have appropriate section headers, so the correct file is as follows:

$ cat /etc/systemd/network/10-netplan-br0.network.d/ipv6_pd_ra.conf
[Network]
IPv6SendRA=yes
DHCPv6PrefixDelegation=yes

If the ISP gives you a /60 (or /48, /52, /56) prefix delegation on request, and you want one, then the following works (ISP-specific, YMMV):

$ cat /etc/systemd/network/10-netplan-enp1s0.network.d/ipv6_pd.conf
[DHCPv6]
PrefixDelegationHint=::/60