Dear Linux users and administrators,

I have the following problem.

I have installed Linux mint 21 xfce on my computer. It's a desktop. It doesn't seem to have a network card.
I have a Lan network which works fine with other laptops, but not on this one. Connection is random, some times it's fine, other times impossible.

Here are the result of a few networking commands.

ip a

l: lo: <LOOPBACK, UP, lower_up> MTU 65536 qdisk 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

So I enabled multicast after reading on a forum that it might help.

Ifconfig lo

Lo: flags=4169<up,loopback,running,multicast> MTU 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0×10<host>
Loop txqueue 1000 (local loopback)
RX packets 1981 bytes 153310 (153.3 KB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1981 bytes 153310 (153.3 KB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

One thing about my network: it's actually Lan via electric power cables. Not that that should make a difference as it works with my other laptops. I tried quite a few things such a setting up link set lo down, then up again and toggling the options under IP link command but to no avail.

Thank you for your help.

The machine does or does not have a network device? If it doesn't then there will be no network to it.

If it does, what device is it? Is there a kernel module loaded for it?
What network manager are you using, and how do you have it configured?

Can you bring up the ethernet interface manually.

Example, use your own device names, IP addresses, routes.
Need a lot more info.

https://linuxmint.com/documentation.php
https://linuxmint-installation-guide...test/help.html
https://community.linuxmint.com/tutorial/search
https://www.systranbox.com/how-to-se...for-beginners/
https://www.itzgeek.com/how-tos/linu...inux-mint.html

I assume that you have a power line adapter that connects to the desktop with a ethernet cable or maybe USB?

As stated the output of the ip command does not show an ethernet adapter. If it works sometimes and not others it maybe the adapter is failing or maybe using a bad driver. As posted we need to know the adapter type because it isn't displayed in the output of the ip command. FYI lo is a virtual network adapter used by some services that communicate between each other on the system itself and not anything outside of your physical PC.

Hello, I have a ethernet line coming from an adapter on the power lines. It works fine with my laptop.

Here is the outcome of lspci

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Ok so I do have a networking device.

It worked again so I ran ip link show.

Device is called enp3s0

I doubt that it's a hardware broblem because it has never failed on me during a running session. Only on startup

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I am using Networkmanager applet version 1.24.0

It's the default one that comes with Linux 21 xfce.

Hi.

Now that the network is up, here is the result of lspci

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If the ethernet adapter only works sometimes at startup then it is probably a hardware problem. If it would always appear in the output of the lspci command then I might agree it was something else.

I assume the ethernet is a built in device on the motherboard so you can either purchase use a USB or PCI adapter.

Thank you everyone for your help.

I bought a pci ethernet card, it works like a charm.