Another Windows migrant here. I can’t get my ethernet to work but wifi works OK. I am almost certain that when I installed Debian Trixie with KDE Plasma a few weeks ago, ethernet worked but it stopped a day or so later. Info Centre reports:
2: enp0s25: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
link/ether 54:ee:75:52:01:23 brd ff:ff:ff:ff:ff:ff
altname enx54ee75520123
3: enx0050b6c0f7f3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:50:b6:c0:f7:f3 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.92/24 brd 192.168.1.255 scope global dynamic noprefixroute enx0050b6c0f7f3
valid_lft 3419sec preferred_lft 2969sec
inet6 fe80::8437:d694:3204:62ff/64 scope link
valid_lft forever preferred_lft forever
I deleted the wired connection in System Settings | Wi-Fi & Networking and it was recreated which probably suggests the ethernet connection is detected even if the fields there are all blank. Also, the internet traffic plasmoid shows enx0050b6c0f7f3 with around 1/5 of the cumulative traffic of wifi.
I tried the obvious things, just in case. I disabled the firewall, restarted the router, deleted the wired connection, played with settings in Wi-Fi & Networking and tried dhcpcd.
$ sudo dhcpcd
main: control_open: Connection refused
dhcpcd-10.1.0 starting
dev: loaded udev
DUID 00:01:00:01:30:54:2e:d5:00:50:b6:c0:f7:f3
wlp4s0: connected to Access Point: glocal
enp0s25: waiting for carrier
enx0050b6c0f7f3: IAID b6:c0:f7:f3
wlp4s0: IAID 86:9b:42:5e
enx0050b6c0f7f3: soliciting an IPv6 router
wlp4s0: soliciting an IPv6 router
wlp4s0: rebinding lease of 192.168.1.122
wlp4s0: probing address 192.168.1.122/24
enx0050b6c0f7f3: rebinding lease of 192.168.1.216
enx0050b6c0f7f3: leased 192.168.1.216 for 3600 seconds
enx0050b6c0f7f3: adding route to 192.168.1.0/24
enx0050b6c0f7f3: adding default route via 192.168.1.254
and sudo systemctl status NetworkManager.service returns
●NetworkManager.service - Network Manager
Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service;enabled; preset: enabled)
Active:active (running)since Sun 2025-10-12 23:59:31 BST; 47min ago
Invocation: a3faea14d3dc48e29a2e2d27750ca082
Docs: man:NetworkManager(8)
Main PID: 98676 (NetworkManager)
Tasks: 4 (limit: 9149)
Memory: 6.3M (peak: 7.1M)
CPU: 2.457s
CGroup: /system.slice/NetworkManager.service
└─98676 /usr/sbin/NetworkManager --no-daemon
Oct 13 00:03:10 tpkde NetworkManager[98676]: <info> [1760310190.8454] dhcp4 (wlp4s0): activation: beginning transaction (timeout in 45 seconds)
Oct 13 00:03:10 tpkde NetworkManager[98676]: <info> [1760310190.8623] dhcp4 (wlp4s0): state changed new lease, address=192.168.1.85, acd pending
Oct 13 00:03:11 tpkde NetworkManager[98676]: <info> [1760310191.0217] dhcp4 (wlp4s0): state changed new lease, address=192.168.1.85
Oct 13 00:03:11 tpkde NetworkManager[98676]: <info> [1760310191.0237] policy: set 'glocal' (wlp4s0) as default for IPv4 routing and DNS
Oct 13 00:03:11 tpkde NetworkManager[98676]: <info> [1760310191.0440] device (wlp4s0): state change: ip-config -> ip-check (reason 'none', managed-type: 'full')
Oct 13 00:03:11 tpkde NetworkManager[98676]: <info> [1760310191.0839] device (wlp4s0): state change: ip-check -> secondaries (reason 'none', managed-type: 'full')
Oct 13 00:03:11 tpkde NetworkManager[98676]: <info> [1760310191.0841] device (wlp4s0): state change: secondaries -> activated (reason 'none', managed-type: 'full')
Oct 13 00:03:11 tpkde NetworkManager[98676]: <info> [1760310191.0855] device (wlp4s0): Activation: successful, device activated.
Oct 13 00:03:11 tpkde NetworkManager[98676]: <info> [1760310191.1033] audit: op="statistics" interface="wlp4s0" ifindex=4 args="2000" pid=1511 uid=1000 result="succe>
Oct 13 00:33:10 tpkde NetworkManager[98676]: <info> [1760311990.8671] dhcp4 (wlp4s0): state changed new lease, address=192.168.1.85
Not sure if this is relevant, but DCHP is handled by pi.hole on a Raspberry Pi. This has been working serving multiple devices for a long time without issues. Also, this is temporarily a dual boot Windows/Linux setup. When I log out and into Windows, everything works as ever.
After several days trying, I ran out of ideas. Can someone help please.
EDIT: SOLVED! In case it helps others, reading https://wiki.debian.org/NetworkManager closely, I ran nmcli device which showed that specific ethernet interface as ‘unmanaged’. I am not sure why. Then, I followed the instructions below:
If you want NetworkManager to handle interfaces that are enabled in
/etc/network/interfaces:Set
managed=truein a drop-in file in/etc/NetworkManager/NetworkManager.conf.d/or directly in/etc/NetworkManager/NetworkManager.conf.
Debian documentation could be more accessible, but it is invaluable. Thanks all for your help.
Typically my debugging process goes like this :
- error message? Search for it online with the most unique keyword that aren’t machine specific
- solutions provided?
- solution understood? try it then loop back, writing notes in own wiki
- solution not understood? bookmark it then try understood solutions first, if not try and loop back
- solutions provided?
- no error message?
- find where the error message is!
- what actually produce the error from the top of the stack? end-user software? service? kernel? hardware? where do they put logs?
- if logs exist and verbosity is not sufficient, increase verbosity and reproduce the problem
- what actually produce the error from the top of the stack? end-user software? service? kernel? hardware? where do they put logs?
- if no verbose enough error message can be obtained, repeat the situation in various conditions
- does any condition make it work?
- search on the difference between the working and non-working condition
- backtrack one layer up the stack, e.g. if end-user software does not change, try service, etc
- does this one provide logs?
- does any condition make it work?
- find where the error message is!
So… it’s basically always the same, namely try the lazy way (error log search) and if that’s not enough, try further down the stack or more unknown BUT always get information out the try.
TL;DR: I have no idea but if another new machine (e.g. phone) can connect then DHCP works. FWIW NetworkManager logs are in
journalctl -u NetworkManagerand you can manually add/remove Ethernet connections. I’d physically unplug then plug back the cable with WiFi disabled.Also FWIW if I wouldn’t get an answer within few hours and I knew for a fact that with a fresh install it worked, I’d re-install.
It’s perfectly fine to do the process again as it insures your files are safe (either working backup or separate disks, or ideally both) and you know what software is relevant for you, that your configuration files are well known, etc.
Installing a distribution should be a painless and quick process.
- error message? Search for it online with the most unique keyword that aren’t machine specific
Boot into a live usb. They’re great for debugging stuff like this and giving you some clues.
If it works, it’s not a hardware or windows issue. If it doesn’t, it might be.
Good idea. With the live USB my ethernet works fine right from the start. So, it’s not hardware or windows. The one difference I see between the live USB and my current setup is that in the live USB session
sudo systemctl status NetworkManager.servicereturns also the line below which is missing when I execute the command in my actual setup:audit: op="statistics" interface="enx0050b6cOf7f3" if index=3 args="2000" pid= 1957 uid=1000 result="success"But Info Center in KDE Plasma lists “enx0050b6cOf7f3” as in my original post.
So, ethernet hardware functions, it works as expected with live USB and Windows. In the debian setup it is detected with an inet address, but NetworkManager ignores it.
DHCP also works – my wifi connection in this debian setup works, as do several devices connected to wifi and ethernet.
If you are dual booting make sure that windows fast boot is disabled.
Fast boot is a bastardized version of hibernation which can keep hardware “in use” by windows if any other OS tries to use the hardware.
One of the common issues is ethernet & wifi not working or not connecting.
Interesting. Just tested, and my ethernet works in a live USB session, so it doesn’t look like it is locked by Windows. Also, I have been properly shutting down, only logging into debian for a couple of weeks but the problem persists.
Interesting. I thought that all but the disk and CMOS were stateless once powered down for hibernation, but I’d love to hear from someone with expertise on how other components know that they were hibernated under Windows.
It’s not a true hibernation state hence my statement “Fast boot is a bastardized version of hibernation”.
It’s a hybrid sleep/hibernate system that causes more problems than it should.
Not all hardware works with it, it causes problems with updates and some software does not play nicely with it.
I know of a number of business IT departments that disable it company wide as it is a considerable source of problems.
They don’t know, that’s the problem
