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I got a new work laptop, switching from an old HP Elitebook 8560w to a new 850 G5. Everything seems to be working correctly except for the wired Ethernet connection.

There's a question mark on the network connection icon on the upper right corner of the screen. While on Ethernet, I'm able to ping anything and I'll get a response:

ping google.com
PING google.com (172.217.22.174) 56(84) bytes of data.
64 bytes from arn09s11-in-f174.1e100.net (172.217.22.174): icmp_seq=1 ttl=45 time=8.43 ms
64 bytes from arn09s11-in-f174.1e100.net (172.217.22.174): icmp_seq=2 ttl=45 time=8.68 ms
64 bytes from arn09s11-in-f174.1e100.net (172.217.22.174): icmp_seq=3 ttl=45 time=8.65 ms
64 bytes from arn09s11-in-f174.1e100.net (172.217.22.174): icmp_seq=4 ttl=45 time=8.62 ms

But actually connecting somewhere on a browser or trying to, for example, establish a telnet connection will immediately fail.

Trying 172.217.22.174...
Trying 2a00:1450:400f:80b::200e...
telnet: Unable to connect to remote host: Network is unreachable

Similarly, an UDP connection fails:

nc -z -v google.com 80
nc: connect to google.com port 80 (tcp) failed: Connection refused
nc: connect to google.com port 80 (tcp) failed: Network is unreachable

I don't have a network proxy enabled, at least based on Ubuntu's network settings. It doesn't seem to be a DNS problem as ping and nslookup seem to be working and providing the correct answers. Here's the relevant bits of sudo lshw -C network for reference:

 *-network
       description: Ethernet interface
       product: Ethernet Connection (4) I219-V
       vendor: Intel Corporation
       physical id: 1f.6
       bus info: pci@0000:00:1f.6
       logical name: enp0s31f6
       version: 21
       serial: b0:0c:d1:42:60:4f
       size: 1Gbit/s
       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 duplex=full firmware=0.1-4 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s
       resources: irq:145 memory:ba400000-ba41ffff
  *-network
       description: Ethernet interface
       physical id: 2
       logical name: enp0s20f0u3c2
       serial: 02:1e:10:1f:00:00
       capabilities: ethernet physical
       configuration: broadcast=yes driver=cdc_ether driverversion=22-Aug-2005 firmware=CDC Ethernet Device link=no multicast=yes

And $ ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: enp0s31f6: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether b0:0c:d1:42:60:4f brd ff:ff:ff:ff:ff:ff
    inet 10.110.61.55/24 brd 10.110.61.255 scope global dynamic noprefixroute enp0s31f6
       valid_lft 691196sec preferred_lft 691196sec
    inet6 fe80::d0ea:fad4:2d50:eae9/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: enp0s20f0u3c2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether 02:1e:10:1f:00:00 brd ff:ff:ff:ff:ff:ff
4: wlp2s0: <BROADCAST,MULTICAST> mtu 1500 qdisc mq state DOWN group default qlen 1000
    link/ether a0:a4:c5:6b:d4:38 brd ff:ff:ff:ff:ff:ff

The obvious thing to note, I guess, is the lack of eth0 interface. Which means... I don't know what that means.

I should emphasise that my old laptop, also running Ubuntu 18.04, works perfectly fine with the exact same Ethernet connection and the exact same cable. Also, my new laptop works perfectly fine with a wireless connection, so the problem is solely with a wired one.

It's probably not about my installation either; I couldn't establish a wired connection with the USB stick Ubuntu either, and reinstalling the OS a couple of times didn't help.

  • In recent Linux you will not see eth0, naming changed some time ago. enp0s31f6 is your ethernet port, enp0s20f0u3c2 is ethernet over USB I think. – marosg Jun 24 '19 at 6:02
  • Just a wild guess - is this some corporate environment where some MAC filtering could be happening? And your new MAC is not allowed? – marosg Jun 24 '19 at 6:05
  • It's a good guess. It is a corporate environment, yes. I don't know the details on security, but it's entirely possible it's something like that. None of my coworkers are having the same problem, though, and the company helpdesk deals in Windows only... I'll test the laptop with my home ethernet later today, see if it'll work there. – PlanB Jun 24 '19 at 6:08
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You talk about wired connection, but ip a output shows you are using wifi (wlp2s0 interface). Your wired connections enp0s... show no IP in one case and no cable in second case

| improve this answer | |
  • My mistake. I was using my wireless while I did the ip a. I edited my question to show the output I get while using my ethernet connection only. – PlanB Jun 24 '19 at 5:59
  • Good spotting. It might help the OP to include the parts of their output that shows that it has no IP and no connection. e.g. "NO-CARRIER" usually means no wire is connected between the device and the switch. – tu-Reinstate Monica-dor duh Jun 24 '19 at 6:00

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