I recently stumbled on this issue. While I understand that IP_FREEBIND
could be a solution, I think that changing "network.target" by
"network-online.target" should be considered anyway.
From the official systemd documentation: "network.target has very
little meaning during start-up"
(https://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/).
So switching "network.target" by "network-online.target" improves
reliability since it makes apache2 work when the network initialization
is a little slow.
I don't see any downside to that, am I missing something?