No. That’s the short of it.
Longer version starts with me setting up my new Ubuntu server and deciding to use
netplan to setup network interfaces. Nothing too big. Just a few bonds here and there. And all seemed fine until I tried to setup email and noticed the following message in syslog:
postfix/smtp: connect to alt1.aspmx.l.google.com[18.104.22.168]:25: Connection timed out
postfix/smtp: connect to aspmx5.googlemail.com[2607:f8b0:4002:c08::1b]:25: Network is unreachable
Once I double-checked, I noticed syslog was right – I only had link-local address assigned to interface. Ok, so DHCPv6 only turns on DHCP and not prefix delegation I use for my network. Easy-peasy, that’s surely matter of just turning on the correct setting…
Or finding a matching bug. Yep, prefix delegation that’s perfectly valid and well supported IPv6 address allocation method is not supported.
But ticket did solve my problem. As advised, I simply reverted to use
networkd (don’t forget to use
systemctl enable systemd-networkd).
PS: Here are my networkd files that work with IPv6 PD.