[GTALUG] Network disabled on PC after last update

[D. Hugh Redelmeier]

| From: sciguy via talk <talk at gtalug.org>
| To: GTALUG Talk <talk at gtalug.org>

Posting one message to two mailing lists is called "crossposting" and 
it often leads to mixups.  For example, I have no idea what has been said 
in response to your original post on the ubuntu mailing list.

I'm hampered by not using Ubuntu, but I'll try to be helpful.

You didn't give the info that Arun asked for.  It might be useful.

Apr 30 09:32:42 rivendell NetworkManager[2015]: <info>  [1619789562.1306] ifupdown: management mode: unmanaged
Apr 30 09:32:42 rivendell NetworkManager[2015]: <warn>  [1619789562.3309] ifupdown: interfaces file /etc/network/interfaces doesn't exist

I don't know if these matter or just indicate you are not using legacy 
network configuration:

| Here are some key lines that got my attention:
| 
| Apr 30 09:32:43 rivendell NetworkManager[2015]: <info>  [1619789563.0888] device (lo): carrier: link connected
| Apr 30 09:32:43 rivendell NetworkManager[2015]: <info>  [1619789563.0890] manager: (lo): new Generic device (/org/freedesktop/NetworkManager/Devices/1)

(lo) is the loopback device.  It has no actual hardware.  It's just a
way of talking to your own machine over.  You should be able to
	ping 127.0.0.1

Looking at your log, most relevant lines refer to devince eno1.

| Apr 30 09:32:43 rivendell NetworkManager[2015]: <info>  [1619789563.0896] manager: (eno1): new Ethernet device (/org/freedesktop/NetworkManager/Devices/2)
| Apr 30 09:32:43 rivendell NetworkManager[2015]: <info>  [1619789563.5762] settings: (eno1): created default wired connection 'Wired connection 1'
| Apr 30 09:32:43 rivendell NetworkManager[2015]: <info>  [1619789563.6633] device (eno1): state change: unmanaged -> unavailable (reason 'managed', sys-iface-state: 'external')
| Apr 30 09:32:43 rivendell NetworkManager[2015]: <warn>  [1619789563.9481] Error: failed to open /run/network/ifstate

This last line might or might not be important.  On my Fedora 33
system I don't have a /run/network directory.

| It then tries again several times. If I interpret this correctly, tt seems to
| make a connecion, then by the fifth message there is a "state change" to
| "unmanaged". Any ideas as to what would cause this?

>From then on, things flap around in failing ways.

More of syslog (beyond network manager) might be informative.