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 (22.214.171.124) 56(84) bytes of data. 64 bytes from arn09s11-in-f174.1e100.net (126.96.36.199): icmp_seq=1 ttl=45 time=8.43 ms 64 bytes from arn09s11-in-f174.1e100.net (188.8.131.52): icmp_seq=2 ttl=45 time=8.68 ms 64 bytes from arn09s11-in-f174.1e100.net (184.108.40.206): icmp_seq=3 ttl=45 time=8.65 ms 64 bytes from arn09s11-in-f174.1e100.net (220.127.116.11): 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 18.104.22.168... 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.