After update, networking is now broken

[Steve the Pocket]

I installed some automatic updates the other day, and now the computer can't connect to the Internet. It's telling me "Wired interface (enp0s25): IP connection was unavailable". I looked up some guides on restarting the network processes, and tellingly all of them came back with errors saying no such program was installed:

$ sudo systemctl restart networking
Failed to restart networking.service: Unit networking.service not found.
$ sudo service network-manager restart
Failed to restart network.manager.service: Unit network-manager.service not found.
$ ifdown eth0
Command 'ifdown' not found, but can be installed with:
sudo apt install ifupdown       # version 0.8.35ubuntu2, or
sudo apt install netscript-2.4  # version 5.5.3

I take it that's the source of my problems right there, the fact that neither networking nor network-manager is on here at all. Lord knows where they went, or why, but I assume one of them is a mandatory component of having a working network card. Assuming that I'm right about that, how do I get them back without a way to download them?

[Snowhog]

Boot into the previous kernel -- for now.

[ajcm73]

I have the same problem with 5.8.0-41 generic kernel and with the previous kernel 5.8.0-38 fails too.

[jglen490]

I have the same problem with 5.8.0-41 generic kernel and with the previous kernel 5.8.0-38 fails too.

With any kernel, if a hardware component isn't working, then it's due to a driver not being found with the kernel. Network drivers can be hit or miss in Linux, depending on the make and model of the specific chip used in the network device. There are utilities in Linux that can help identify the network device down to the chip. One of those utilities is lshw, which is run at the command line.

Open a konsole, and enter:

sudo lshw -c network

The output should look something like this, depending on your exact configuration:

[john@HP-ENVY-x360 boot]$ sudo lshw -c network
[sudo] password for john: 
 *-network                 
      description: Wireless interface
      product: Wi-Fi 6 AX201
      vendor: Intel Corporation
      physical id: 14.3
      bus info: pci@0000:00:14.3
      logical name: wlo1
      version: 20
      serial: fc:44:82:a3:c7:c6
      width: 64 bits
      clock: 33MHz
      capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless
      configuration: broadcast=yes driver=iwlwifi driverversion=5.8.0-41-generic firmware=55.d9698065.0 QuZ-a0-hr-b0-55.u ip=192.168.5.84 latency=0 link=yes multicast=yes wireless=IEEE 802.11
      resources: iomemory:600-5ff irq:16 memory:6003244000-6003247fff

[ajcm73]

Thanks, Today I start the pc and the network works fine and I don't know why. Yesterday I plugged my old "d-link usb dwa-131 wireless-n nano adapter" and it worked without problems.

sudo lshw -c network
[sudo] contrase?a para javier:
*-network
description: Ethernet interface
product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
vendor: Realtek Semiconductor Co., Ltd.
physical id: 0
bus info: pci@0000:02:00.0
logical name: enp2s0
version: 0c
serial: e0:d5:5e:43:ac:d0
size: 1Gbit/s
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet
physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=r8169 driverve
rsion=5.8.0-41-generic duplex=full firmware=rtl8168g-2_0.0.1 02/06/13 ip=192
.168.0.184 latency=0 link=yes multicast=yes port=MII speed=1Gbit/s
resources: irq:16 ioport:d000(size=256) memory:ef100000-ef100fff memo
ry:e2100000-e2103fff

[jglen490]

Thanks, Today I start the pc and the network works fine and I don't know why. Yesterday I plugged my old "d-link usb dwa-131 wireless-n nano adapter" and it worked without problems ...

It's very possible the older wifi card could have brought in a needed driver. It's good to hear your network connection is working.

[Steve the Pocket]

By the way, my problem turned out to be the router being on the fritz; it was serving wifi but not Ethernet for some reason and had to be rebooted.

Still curious as to what Kubuntu uses to do network stuff if it doesn't include the networking or network-manager packages by default, though. Seeing how every single guide for troubleshooting network stuff assumes you have those.

[jglen490]

As ffar as I know Kubuntu does. Maybe there's an install option that negates that.

[ajcm73]

Hello again:

Kubuntu 20.04, kubuntu 20.10, ubuntu 20.10 ethernet and WiFi fails but on kde neon works fine.

Ethernet fails because it doesn't find an IP on enp2s0 and WiFi works fine some minutes and so fails and after works fine, etc.

The pc is connected at secondary router not principal .

Thanks.

[oshunluvr]

The issue is likely kernel related so what kernels are you booting to in all those options? What does your netplan configuration looks like on all three?

[ajcm73]

When I am installing kubuntu i have Internet but after boot the first time Internet fails

[ajcm73]

I think it was kernel 5.4.69. When I am installing kubuntu I have ethernet access but after when I boot the system first time I have not internet.

[ajcm73]

Hello:

Kde Neon testing use kernel 5.4.0-67 its works fine. I suppose that the kernels 5.4.x -70 and up fails. Kernels of kubuntu 20.04.2 and 20.10 and ubuntu 20.04.2.

I am sorry, the debian testing problem is that I don?t boot in graphic mode.

I am windows 10 user but I want learn linux, I like kde , I prefer kubuntu because is more manageable, have softwre sources, can add nvidia drivers. I like the new software and new normal releases,

Today in kde neon updated the kernel from 5.4.0-64 to kernel 5.11.6 and kde neon works fine and network too. Maybe I must update the kernel of kubuntu 20.10 ( 5.8.x) to last stable kernel to see if the network works for me.

I go to install kubuntu 20.10 again, I like knows that information of my network you need, whats command must put in konsole.

Thanks.

[ajcm73]

Kubuntu 20.10 install:

At 94% installer crash. Then I reboot in recovery mode and repair packets. I am writing from kubuntu 20.10 with usb wifi.

The install had 5.8.25 kernel, after install 5.8.44, and after update 5.8.45 but this don't works and then I am using 5.8.44

[ajcm73]

javier@javier-H110M-S2:~$ sudo lshw -c network
[sudo] contrase?a para javier:
*-network
description: Ethernet interface
product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
vendor: Realtek Semiconductor Co., Ltd.
physical id: 0
bus info: pci@0000:02:00.0
logical name: enp2s0
version: 0c
serial: e0:d5:5e:43:ac:d0
size: 1Gbit/s
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix vpd bus_master cap_list ethernet
physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=r8169 driverve
rsion=5.8.0-44-generic duplex=full firmware=rtl8168g-2_0.0.1 02/06/13 latenc
y=0 link=yes multicast=yes port=MII speed=1Gbit/s
resources: irq:16 ioport:d000(size=256) memory:ef100000-ef100fff memo
ry:e2100000-e2103fff
*-network
description: Wireless interface
physical id: 2
bus info: usb@1:8
logical name: wlxc8d3a3f44747
serial: c8:d3:a3:f4:47:47
capabilities: ethernet physical wireless
configuration: broadcast=yes driver=rtl8192cu driverversion=5.8.0-44-
generic firmware=N/A ip=192.168.0.104 link=yes multicast=yes wireless=IEEE 8
02.11
javier@javier-H110M-S2:~$