[Post-Install] Kubuntu 26.04 Network device not working/showing after update or reboot

[cherryForge]

hi

I installed Kubuntu 26.04 and everything worked nice. Internet connection was working, i did updates and after that Internet connection stopped working and my network device is not shown in system manager.
After a fresh install everything was working nice again. I did run the updates again to check which one is causing the problem. But this time my network worked until the next reboot. After first reboot device is not shown/recognized again and no internet connection.

I tried commands, that helped others to fix network connection, but nothing worked with kubuntu.

What can I try to fix this? Which update is causing this and how to remove it?

Thank You

[die.boer]

are you dual booting with windows?
how do you connect , wifi or ethernet or USB adapter?
don't know what commands you tried , so ...please post output of these commands.

lspci -nnk | grep -A5 -iE "network|ethernet|wireless"

lspci -nnk

uname -r

another test to try is to boot the previous kernel from GRUB:
Hold Shift (BIOS) or Esc (UEFI) during boot.
Choose Advanced options for Kubuntu.
Select the older kernel.

[kc1di]

We will need a bit more info to be of much help post the outputs of the command requested by die.boer and also the output of

rfkill list

Also give use as much info about the machine as you can.

[die.boer]

Also give use as much info about the machine as you can.

can use

inxi -Fazxx

(or can copy/paste this in terminal )


echo "===== SYSTEM ====="
uname -a
echo

echo "===== OS ====="
cat /etc/os-release
echo

echo "===== CPU ====="
lscpu
echo

echo "===== MEMORY ====="
free -h
echo

echo "===== PCI DEVICES ====="
lspci -nnk
echo

echo "===== USB DEVICES ====="
lsusb
echo

echo "===== DISKS ====="
lsblk

[cherryForge]

i tried: lshw -C network | grep driver and sudo lshw -C network for example

i do not dualboot

i use ethernet (cable)

in advanced boot options i only see normal and recovery mode, can´t see an option to choose older kernel (in recovery mode or elswhere)

if i open system monitor (where you see cpu and ram usage) it says something like : this site has missing sensors, display is incorrect (i can try to set them manually, but i dont think this will help)
(cant switch to english whitout internet, hope my translation is close enough)

rfkill list -> no output

inxi -Fazxx -> inxi not installed, cant do that whitout internet :P

the othe commands gave some output i just need find a way to put them here.

it´s an old motherboard: gigabyte H77-DS3H, but network was working before update so the age shouldn´t matter?

edit: i try the echo commands too

[die.boer]

the othe commands gave some output i just need find a way to put them here.

you cannot select the output in terminal and copy and paste it here ?
output of this too please

sudo lshw -C network

and

lspci -nnk | grep -A5 -i ethernet

[cherryForge]

xxx@xxx:~$ echo "===== SYSTEM ====="
uname -a
echo
===== SYSTEM =====
Linux xxxxxxx 7.0.0-14-generic #14-Ubuntu SMP PREEMPT_DYNAMIC Mon Apr 13 11:09:53 UTC 2026 x86_64 GNU/Linux

xxx@xxx:~$ echo "===== OS ====="
cat /etc/os-release
echo
===== OS =====
PRETTY_NAME="Ubuntu 26.04 LTS"
NAME="Ubuntu"
VERSION_ID="26.04"
VERSION="26.04 LTS (Resolute Raccoon)"
VERSION_CODENAME=resolute
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=resolute
LOGO=ubuntu-logo

xxx@xxx:~$ echo "===== CPU ====="
lscpu
echo
===== CPU =====
Architektur: x86_64
CPU Operationsmodus: 32-bit, 64-bit
Adressgrößen: 36 bits physical, 48 bits virtual
Byte-Reihenfolge: Little Endian
CPU(s): 4
Liste der Online-CPU(s): 0-3
Anbieterkennung: GenuineIntel
Modellname: Intel(R) Core(TM) i5-3450 CPU @ 3.10GHz
Prozessorfamilie: 6
Modell: 58
Thread(s) pro Kern: 1
Kern(e) pro Sockel: 4
Sockel: 1
Stepping: 9
Skalierung der CPU(s): 60%
Maximale Taktfrequenz der CPU: 3500,0000
Minimale Taktfrequenz der CPU: 1600,0000
BogoMIPS: 6186,09
Markierungen: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clf
lush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm constant_
tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmp
erf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pc
id sse4_1 sse4_2 popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_l
m cpuid_fault epb pti ssbd ibrs ibpb stibp tpr_shadow flexpriority ept vpid
fsgsbase smep erms xsaveopt dtherm ida arat pln pts vnmi md_clear flush_l1
d
Virtualisierungsfunktionen:
Virtualisierung: VT-x
Caches (Gesamtsumme):
L1d: 128 KiB (4 Instanzen)
L1i: 128 KiB (4 Instanzen)
L2: 1 MiB (4 Instanzen)
L3: 6 MiB (1 Instanz)
NUMA:
NUMA-Knoten: 1
NUMA-Knoten0 CPU(s): 0-3
Schwachstellen:
Gather data sampling: Not affected
Ghostwrite: Not affected
Indirect target selection: Not affected
Itlb multihit: KVM: Mitigation: Split huge pages
L1tf: Mitigation; PTE Inversion; VMX conditional cache flushes, SMT disabled
Mds: Mitigation; Clear CPU buffers; SMT disabled
Meltdown: Mitigation; PTI
Mmio stale data: Not affected
Old microcode: Not affected
Reg file data sampling: Not affected
Retbleed: Not affected
Spec rstack overflow: Not affected
Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl
Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Spectre v2: Mitigation; Retpolines; IBPB conditional; IBRS_FW; STIBP disabled; RSB fill
ing; PBRSB-eIBRS Not affected; BHI Not affected
Srbds: Vulnerable: No microcode
Tsa: Not affected
Tsx async abort: Not affected
Vmscape: Mitigation; IBPB before exit to userspace


xxx@xxx:~$ echo "===== MEMORY ====="
free -h
echo
===== MEMORY =====
gesamt benutzt frei gemns. Puffer/Cache verfügbar
Speicher: 23Gi 1,6Gi 20Gi 225Mi 2,0Gi 21Gi
Auslager: 23Gi 0B 23Gi

xxx@xxx:~$ echo "===== PCI DEVICES ====="
lspci -nnk
echo
===== PCI DEVICES =====
00:00.0 Host bridge [0600]: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller [xxxx:xxxx] (rev 09)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: ivb_uncore
Kernel modules: ie31200_edac
00:02.0 VGA compatible controller [0300]: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller [xxxx:xxxx] (rev 09)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: i915
Kernel modules: i915
00:14.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: xhci_hcd
Kernel modules: xhci_pci
00:16.0 Communication controller [0780]: Intel Corporation 7 Series/C216 Chipset Family MEI Controller #1 [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: mei_me
Kernel modules: mei_me
00:1a.0 USB controller [0c03]: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #2 [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: ehci-pci
Kernel modules: ehci_pci
00:1b.0 Audio device [0403]: Intel Corporation 7 Series/C216 Chipset Family High Definition Audio Controller [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: snd_hda_intel
Kernel modules: snd_hda_intel
00:1c.0 PCI bridge [0604]: Intel Corporation 7 Series/C216 Chipset Family PCI Express Root Port 1 [xxxx:xxxx] (rev c4)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: pcieport
Kernel modules: shpchp
00:1c.2 PCI bridge [0604]: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 3 [xxxx:xxxx] (rev c4)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: pcieport
Kernel modules: shpchp
00:1c.3 PCI bridge [0604]: Intel Corporation 82801 PCI Bridge [xxxx:xxxx] (rev c4)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: pcieport
00:1d.0 USB controller [0c03]: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #1 [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: ehci-pci
Kernel modules: ehci_pci
00:1f.0 ISA bridge [0601]: Intel Corporation H77 Express Chipset LPC Controller [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: lpc_ich
Kernel modules: lpc_ich
00:1f.2 IDE interface [0101]: Intel Corporation 7 Series/C210 Series Chipset Family 4-port SATA Controller [IDE mode] [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: ata_piix
Kernel modules: pata_acpi
00:1f.3 SMBus [0c05]: Intel Corporation 7 Series/C216 Chipset Family SMBus Controller [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: i801_smbus
Kernel modules: i2c_i801
00:1f.5 IDE interface [0101]: Intel Corporation 7 Series/C210 Series Chipset Family 2-port SATA Controller [IDE mode] [xxxx:xxxx] (rev 04)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: ata_piix
Kernel modules: pata_acpi
02:00.0 Ethernet controller [0200]: Qualcomm Atheros AR8161 Gigabit Ethernet [xxxx:xxxx] (rev 10)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: alx
Kernel modules: alx
03:00.0 PCI bridge [0604]: Intel Corporation 82801 PCI Bridge [xxxx:xxxx] (rev 41)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]

xxx@xxx:~$ echo "===== USB DEVICES ====="
lsusb
echo
===== USB DEVICES =====
Bus 001 Device 001: ID xxxx:xxxx Linux Foundation 2.0 root hub
Bus 001 Device 002: ID xxxx:xxxx Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID xxxx:xxxx Linux Foundation 2.0 root hub
Bus 002 Device 002: ID xxxx:xxxx xxxxxxx Keyboard
Bus 002 Device 003: ID xxxx:xxxx Genesys Logic, Inc. Hub
Bus 002 Device 011: ID xxxx:xxxx xxxxxxx Mouse
Bus 003 Device 001: ID xxxx:xxxx Linux Foundation 3.0 root hub
Bus 004 Device 001: ID xxxx:xxxx Linux Foundation 2.0 root hub
Bus 004 Device 002: ID xxxx:xxxx Intel Corp. Integrated Rate Matching Hub

xxx@xxx:~$ echo "===== DISKS ====="
lsblk
===== DISKS =====
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
loop0 7:0 0 4K 1 loop /snap/bare/5
loop1 7:1 0 74M 1 loop /snap/core22/2411
loop2 7:2 0 66,8M 1 loop /snap/core24/1643
loop3 7:3 0 66,8M 1 loop /snap/core24/1587
loop4 7:4 0 184,9M 1 loop /snap/element-desktop/203
loop5 7:5 0 91,7M 1 loop /snap/gtk-common-themes/1535
loop6 7:6 0 62,2M 1 loop /snap/ffmpeg-2204/126
loop7 7:7 0 264K 1 loop /snap/gtk-theme-breeze/8
loop8 7:8 0 273,7M 1 loop /snap/firefox/8107
loop9 7:9 0 606,1M 1 loop /snap/gnome-46-2404/153
loop10 7:10 0 248,5M 1 loop /snap/firefox/8387
loop11 7:11 0 13,2M 1 loop /snap/icon-theme-breeze/5
loop12 7:12 0 1,5G 1 loop /snap/kf5-core22/3
loop13 7:13 0 371,5M 1 loop /snap/krita/109
loop14 7:14 0 49,3M 1 loop /snap/snapd/26865
loop15 7:15 0 395M 1 loop /snap/mesa-2404/1165
loop16 7:16 0 227,6M 1 loop /snap/thunderbird/1057
loop17 7:17 0 227,7M 1 loop /snap/thunderbird/1117
sda 8:0 0 447,1G 0 disk
├─sda1 8:1 0 8M 0 part
├─sda2 8:2 0 512M 0 part /boot
├─sda3 8:3 0 23,4G 0 part [SWAP]
├─sda4 8:4 0 68,4G 0 part /swap
│ /
├─sda5 8:5 0 48,8G 0 part
├─sda6 8:6 0 48,8G 0 part
└─sda7 8:7 0 257,2G 0 part /home
sr0 11:0 1 1024M 0 rom

xxx@xxx:~$ lspci -nnk | grep -A5 -iE "network|ethernet|wireless"
02:00.0 Ethernet controller [0200]: Qualcomm Atheros AR8161 Gigabit Ethernet [xxxx:xxxx] (rev 10)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]
Kernel driver in use: alx
Kernel modules: alx
03:00.0 PCI bridge [0604]: Intel Corporation 82801 PCI Bridge [xxxx:xxxx] (rev 41)
Subsystem: Gigabyte Technology Co., Ltd Device [xxxx:xxxx]



needed to find a usb-storage first

[die.boer]

ok ,now please the outputs of

ip link

sudo lshw -C network

nmcli device

[cherryForge]

yyy@yyy:~$ ip link
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: enp2s0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN mode DEFAULT group default qlen 1000
link/ether xx: xx: xx: xx: xx: xx brd ff:ff:ff:ff:ff:ff
altname enyyyyyyyyyy
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default qlen 1000
link/ether yy: yy: yy: yy: yy: yy brd ff:ff:ff:ff:ff:ff


yyy@yyy:~$ nmcli device
DEVICE TYPE STATE CONNECTION
lo loopback verbunden (extern) lo
virbr0 bridge verbunden (extern) virbr0
enp2s0 ethernet nicht verfügbar --


yyy@yyy:~$ sudo lshw -C network
*-network
Beschreibung: Ethernet interface
Produkt: AR8161 Gigabit Ethernet
Hersteller: Qualcomm Atheros
Physische ID: 0
Bus-Informationen: pci@0000:02:00.0
Logischer Name: enp2s0
Version: 10
Seriennummer: xx: xx: xx: xx: xx: xx
Kapazität: 1Gbit/s
Breite: 64 bits
Takt: 33MHz
Fähigkeiten: pm pciexpress msi msix bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
Konfiguration: autonegotiation=on broadcast=yes driver=alx driverversion=7.0.0-14-generic latency=0 link=no multicast=yes port=twisted pair
Ressourcen: irq:18 memory: xxxxxxx-yyyyyyyy ioport: xxx(Größe=128)

[Qqmike]

If I may, I'll insert this side comment.
I believe I recall this issue keeps popping up through several Kubuntu versions.
I currently have 22.04 and 24.04. I often have the issue you describe:
Get an update, lose my internet connection.
I am always able to get past it by unplugging the Ethernet cable for 15 seconds and plugging it back in,
then the internet is recognized.
I'll be interested in following your thread here.

Edit: You could also maybe re-boot the router, but that's a bit more hassle.

[die.boer]

from the output ...enp2s0: <NO-CARRIER,...>
state DOWN
NO-CARRIER means the network card does not detect a physical Ethernet link. In other words, Kubuntu sees the card, but the card thinks nothing is plugged into it.

give output of this please

sudo dmesg | grep -i alx

and also these

sudo ethtool enp2s0

dpkg -l | grep linux-image

(last 1 to see if you actually have an older kernel available)

[cherryForge]

Qqmike nice to hear from you, any help is welcome.

In my case the issue seams to be more serious, the sensors for up/download etc. are not shown in system monitor.
The taskbar network shows unknown. im pretty sure this had shown diffrent text/symbol before the issue.

Anyways I tried to connect the computer to the internet again (after router reboot), but as expected network still not working.

and some more output:

xxx@xxx:~$ dpkg -l | grep linux-image
ii linux-image-7.0.0-14-generic 7.0.0-14.14 amd64 Signed kernel image generic
iF linux-image-7.0.0-22-generic 7.0.0-22.22 amd64 Signed kernel image generic
iU linux-image-generic 7.0.0-22.22 amd64 Generic Linux kernel image
xxx@xxx:~$ sudo dmesg | grep -i alx
[ x.xxxxxx] alx 0000:02:00.0 eth0: Qualcomm Atheros AR816x/AR817x Ethernet [xx: xx: xx: xx: xx: xx]
[ x.xxxxxx] alx 0000:02:00.0 enp2s0: renamed from eth0
xxx@xxx:~$ sudo ethtool enp2s0
Settings for enp2s0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: Symmetric Receive-only
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: Symmetric
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Speed: Unknown!
Duplex: Unknown! (255)
Auto-negotiation: on
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
MDI-X: Unknown
Current message level: 0x0000xxxx (xxxxx)
link ifup rx_err tx_err hw wol
Link detected: no

[die.boer]

from your output i see this
ii linux-image-7.0.0-14-generic
iF linux-image-7.0.0-22-generic
iU linux-image-generic
which means the update didn't complete succesfully
(ii = installed and configured. / iF = package installation failed / half-configured. / iU = unpacked but not configured.)

run these one by one

sudo dpkg --configure -a

sudo apt --fix-broken install

sudo apt update && sudo apt full-upgrade​

watch carefully for any errors