Arch Linux

stefano

Member

Registered: 2011-04-09

Posts: 258

[SOLVED] Network connection fails to load after blackout

We had a a 30 seconds blackout today, and when my desktop came back up it was no longer able to connect to the network.

All the other computers in the house are .fine, both wired and wireless. It is only my desktop workstation that cannot get on.
I first checked the status of the systemd service:

systemctl status dhcpcd@eno1.service

dhcpcd@eno1.service - dhcpcd on eno1
   Loaded: loaded (/usr/lib/systemd/system/dhcpcd@.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2017-03-31 10:40:17 CDT; 2h 9min ago
  Process: 468 ExecStart=/usr/bin/dhcpcd -q -w %I (code=exited, status=1/FAILURE)

Mar 31 10:40:01 gorgias dhcpcd[468]: eno1: IAID 3a:9a:ed:f1
Mar 31 10:40:01 gorgias dhcpcd[468]: eno1: adding address fe80::adeb:65eb:1459:fb54
Mar 31 10:40:01 gorgias dhcpcd[468]: eno1: soliciting an IPv6 router
Mar 31 10:40:02 gorgias dhcpcd[468]: eno1: soliciting a DHCP lease
Mar 31 10:40:02 gorgias dhcpcd[468]: eno1: carrier lost
Mar 31 10:40:02 gorgias dhcpcd[468]: eno1: deleting address fe80::adeb:65eb:1459:fb54
Mar 31 10:40:17 gorgias systemd[1]: dhcpcd@eno1.service: Control process exited, code=exited status=1
Mar 31 10:40:17 gorgias systemd[1]: Failed to start dhcpcd on eno1.
Mar 31 10:40:17 gorgias systemd[1]: dhcpcd@eno1.service: Unit entered failed state.
Mar 31 10:40:17 gorgias systemd[1]: dhcpcd@eno1.service: Failed with result 'exit-code'.

then looked at the journal:

journalctl -b | grep eno1
[Fri Mar 31 12:51:45 2017] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[Fri Mar 31 12:51:46 2017] e1000e: eno1 NIC Link is Down
[Fri Mar 31 12:51:49 2017] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[Fri Mar 31 12:51:49 2017] e1000e: eno1 NIC Link is Down
[Fri Mar 31 12:51:52 2017] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[Fri Mar 31 12:51:53 2017] e1000e: eno1 NIC Link is Down
[Fri Mar 31 12:52:07 2017] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[Fri Mar 31 12:52:07 2017] e1000e: eno1 NIC Link is Down
[Fri Mar 31 12:52:25 2017] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
[Fri Mar 31 12:52:26 2017] e1000e: eno1 NIC Link is Down
[Fri Mar 31 12:52:43 2017] e1000e: eno1 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx

I frankly have no idea about what is going wrong. The system is up to date
Help greatly appreciated.

Last edited by stefano (2017-03-31 21:38:48)

rsmarples

Member

Registered: 2009-05-12

Posts: 287

Re: [SOLVED] Network connection fails to load after blackout

If you had a blackout, you probably had a power spike hit your network card, or the cabling or the other end it's connected to and fried something with the link state handling.
I recommend trying a new cable, and if that fails, new interfaces either side. Hopefully you have spares and can troubleshoot the faulty component.

Good luck!

stefano

Member

Registered: 2011-04-09

Posts: 258

Re: [SOLVED] Network connection fails to load after blackout

If you had a blackout, you probably had a power spike hit your network card, or the cabling or the other end it's connected to and fried something with the link state handling.
I recommend trying a new cable, and if that fails, new interfaces either side. Hopefully you have spares and can troubleshoot the faulty component.

l replaced the cable and the problem persists, the cable goes from the PC to a switch, which works fine (other computers attached to it have no issues. I switched cables and ports to no avail(. That leaves the NIC on the PC side. However, it is directly on the motherboard, and it is seems unlikely to me that a hardware failure affecting the MB would only touch the NIC. I have no idea how to test the idea though, I do not have a spare NIC card.

All in all, it seems to me it is more likely to be a SW issue.

stefano

Member

Registered: 2011-04-09

Posts: 258

Re: [SOLVED] Network connection fails to load after blackout

UPDATE:

after playing around with the cable and the switch's ports, I managed to get the interface UP. That is,

$> dmesgs | grep e10000e

[     16.712005] e1000e: eno1 NIC Link is Up 1000 Mps Full Duplex, Flow Control: Rx/Tx

The network connection is still down, though and ping is replying "Network is unreachable"

stefano

Member

Registered: 2011-04-09

Posts: 258

Re: [SOLVED] Network connection fails to load after blackout

So it turned out that a reboot of the router is all that's was needed, as I discovered after a few hours.

No idea why only my desktop's  network connection was down while other Archlinux machines in the house had no issues.