Comment 9 for bug 1664844

> - If wan0 is not link up, I wouldn't want that to block
> boot. Maybe my ISP is having trouble. Maybe the dog chewed
> through the cable. I don't know. But I don't to block the
> boot process (and thus the other functions of the router)
> because of it. If I block boot, I can't even SSH into the
> box to figure out what went wrong.

I think this concern is based on an outdated concept of the boot process. Under systemd (which is the only init system for which netplan will be enabled), there is a distinction between 'network' and 'network-online' and only a small number of services will require 'network-online'. ssh is absolutely not one of them.

I think you're still describing a valid bug, in that it is likely useful to distinguish between required and optional interfaces for network-online. But the impact is much less than this.