This is with Fedora 25, x86_64.
I've started to have a problem sometime within the last month, where on
boot I get a message that the ethernet link is up, but when I try to
use it, sometimes it can't be accessed. I've unloaded and reloaded the
ethernet driver, and that worked once, but not another time. If I
power down and restart the modem and router, usually NetworkManager
will recognize the link, though sometimes this take a couple of tries.
If I power up the modem and router, and then boot, NetworkManager
*never* recognizes the link, and I have to usually power down and power
up the modem and router to get NetworkManager to recognize the link.
Once the link is established, it works like it always has, and never
fails.
Is anyone else seeing this? Can you think of any reason this would
start happening barring a bug in NetworkManager?