No Ethernet on Lenovo P50, (`ifplugstatus` reports unplugged) Intel I219-LM network card

by MRule   Last Updated February 21, 2018 14:02 PM


On a Lenovo P50, the network card does not seem to be able to detect Ethernet cables or establish a network connection. The ethernet conection is set-up to be hot-plugged and managed by avahi. The wired connection once worked, but seems to have failed some time in the past six months or so.

Debugging so far

  • Computing support confirms that network ports are working
  • Other machines plugged into network ports work, indicating cables are good
  • Plugging in ethernet cables to laptop does not cause port to light up (but it is not clear that this port has lights)
  • Wireless connection works
  • Network configuration appears ok, common pitfalls not present

System information

$ cat /etc/lsb-release 
$ cat /proc/version
Linux version 4.4.0-112-generic ([email protected]) (gcc version 5.4.0 20160609 (Ubuntu 5.4.0-6ubuntu1~16.04.5) ) #135-Ubuntu SMP Fri Jan 19 11:48:36 UTC 2018
$ lspci | grep Ethernet
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (2) I219-LM (rev 31)
$ sudo lshw -C network
       description: Wireless interface
       product: Wireless 8260
       vendor: Intel Corporation
       physical id: 0
       bus info: [email protected]:04:00.0
       logical name: wlp4s0
       version: 3a
       serial: 44:85:00:a1:31:5a
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=4.4.0-112-generic firmware=16.242414.0 ip= latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
       resources: irq:133 memory:c4c00000-c4c01fff
       description: Ethernet interface
       product: Ethernet Connection (2) I219-LM
       vendor: Intel Corporation
       physical id: 1f.6
       bus info: [email protected]:00:1f.6
       logical name: enp0s31f6
       version: 31
       serial: 50:7b:9d:e4:d8:49
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=3.2.6-k firmware=0.8-3 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:130 memory:c5700000-c571ffff
$ ifconfig
enp0s31f6 Link encap:Ethernet  HWaddr 50:7b:9d:e4:d8:49  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:16 Memory:c5700000-c5720000 

enp0s31f6:avahi Link encap:Ethernet  HWaddr 50:7b:9d:e4:d8:49  
          inet addr:  Bcast:  Mask:
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          Interrupt:16 Memory:c5700000-c5720000 
$ ifplugstatus
lo: link beat detected
enp0s31f6: unplugged
$ cat /etc/network/interfaces
# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

allow-hotplug enp0s31f6
iface enp0s31f6 inet dhcp

The following questions with similar symptoms do not resolve the issue:

Suggested solutions that do not work in this case:

The suggested command ip link set enp1s0 up does not resolve it. The suggested commands ifconfig .. down ... up do not resolve it.

Similar symptoms, but probably unrelated hardware issues:

This issue is common with Realtek cards, and there are several related questions (1234), but this machine has an Intel card.

This question seems specific to a USB Ethernet device, related to hot-plug issues.

This question involves the network interface disappearing entirely, and returning on reboot.

This question is a bit vague and lacks definitive answers.

This question pertains to Ethernet, but the answer is a link to wifi troubleshooting.

This question appears to be different, as it involves the Ethernet adapter being unavailable, wheres it is available on my machine but registers as disconnected.

This question has similar symptoms, but was due to a conflicting configuration from a previous network card.

This question related to a corrupted driver (I think?).

Potentially related questions without resolution

This question may be related (unclear), but does not have an answer. Likewise for this question.

This question was diagnosed as a hardware fault of the network card. It is not clear that it applies in this case. This one seemed also to be a hardware failure. (I would like to rule out other explanations before presuming hardware failure).

Related Questions

Ethernet cable is not detected in Ubuntu

Updated August 23, 2017 12:02 PM

Ubuntu 17.04. install driver for Ethernet Adapter

Updated August 22, 2017 10:02 AM

Lenovo Thunderbolt 3 Dock ethernet 17.04

Updated August 18, 2017 19:02 PM