Comment 15 for bug 510587

I'm not sure if everyone is having the issue here. But if in named.conf you're explicitly binding to a particular address, then you need to *also* configure named to start only after that interface is configured. See https://lists.ubuntu.com/archives/ubuntu-devel/2021-May/041455.html for some fairly recent discussion on this. The exact nature of this has changed over the years since this bug was first opened; since systemd was introduced in 16.04, it's systemd that is relevant. Some users might find that adding After=network-online.target works for them. The ML thread goes more into why this isn't the default.