[SOLVED] Recurring Ethernet Issues Following Updates

sample1693 · 2026-08-06 03:26:12

Hi everyone, I suspect that my Ethernet stops working after certain kernel updates. I say "certain" because after a few days and a few subsequent system updates, it eventually starts working again on its own.

This has happened several times, but I haven't been able to identify a consistent pattern. I'm not even sure if it occurs after every kernel update or only some of them. It seems to resolve itself eventually without me making any changes, which makes it difficult to pinpoint the cause.

Terminal

$ uname -a
Linux desktop 7.1.5-arch1-2 #1 SMP PREEMPT_DYNAMIC Tue, 28 Jul 2026 13:49:51 +0000 x86_64 GNU/Linux

$ lspci -knnd ::200
0a:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8125 2.5GbE Controller [10ec:8125] (rev 05)
	Subsystem: Gigabyte Technology Co., Ltd Device [1458:e000]
	Kernel driver in use: r8169
	Kernel modules: r8169

$ pacman -Qs linux
local/alsa-lib 1.2.16.1-1
    An alternative implementation of Linux sound support
local/alsa-utils 1.2.16-1
    Advanced Linux Sound Architecture - Utilities
local/android-udev 20260423-1
    Udev rules to connect Android devices to your linux box
local/archlinux-keyring 20260727-1
    Arch Linux PGP keyring
local/avahi 1:0.9rc5-1
    Service Discovery for Linux using mDNS/DNS-SD (compatible with Bonjour)
local/base 3-3
    Minimal package set to define a basic Arch Linux installation
local/base-devel 1-2
    Basic tools to build Arch Linux packages
local/bluez-tools 0.2.0-6
    A set of tools to manage Bluetooth devices for Linux
local/brltty 6.9.1-3
    Braille display driver for Linux/Unix
local/dbus-broker 37-3
    Linux D-Bus Message Broker
local/dbus-broker-units 37-3
    Linux D-Bus Message Broker - Service units
local/efibootmgr 18-4
    Linux user-space application to modify the EFI Boot Manager
local/filesystem 2025.10.12-1
    Base Arch Linux files
local/flatpak 1:1.18.0-1
    Linux application sandboxing and distribution framework (formerly xdg-app)
local/fuse2 2.9.9-5
    Interface for userspace programs to export a filesystem to the Linux kernel
local/fuse3 3.18.2-1
    Interface for userspace programs to export a filesystem to the Linux kernel
local/gufw 26.04-2
    Uncomplicated way to manage your Linux firewall
local/hdparm 9.65-3
    A shell utility for manipulating Linux IDE drive/driver parameters
local/ibus 1.5.34-1
    Intelligent input bus for Linux/Unix
local/iptables 1:1.8.13-1
    Linux kernel packet control tool (using nft interface)
local/keyutils 1.6.3-4
    Linux Key Management Utilities
local/kmod 34.2-1
    Linux kernel module management tools and library
local/lib32-alsa-lib 1.2.16.1-1
    An alternative implementation of Linux sound support (32 bit)
local/lib32-keyutils 1.6.3-4
    Linux Key Management Utilities (32-bit)
local/lib32-libxshmfence 1.3.3-1
    a library that exposes a event API on top of Linux futexes (32-bit)
local/lib32-util-linux 2.42.2-1
    Miscellaneous system utilities for Linux (32-bit)
local/libaio 0.3.113-4
    The Linux-native asynchronous I/O facility (aio) library
local/libcap-ng 0.9.3-1
    A library for Linux that makes using posix capabilities easy
local/libiec61883 1.2.0-9
    A higher level API for streaming DV, MPEG-2 and audio over Linux IEEE 1394
local/libnvme 1.16.2-1
    C Library for NVM Express on Linux
local/libraw1394 2.1.2-4
    Provides an API to the Linux IEEE1394 (FireWire) driver
local/libssc 0.4.4-1
    Library for exposing Qualcomm Sensor Core sensors to Linux
local/libtraceevent 1:1.9.0-1
    Linux kernel trace event library
local/libtracefs 1.8.3-1
    Linux kernel trace file system library
local/liburing 2.15-1
    Linux-native io_uring I/O access library
local/libva 2.24.1-1
    Video Acceleration (VA) API for Linux
local/libxshmfence 1.3.3-1
    a library that exposes a event API on top of Linux futexes
local/linux 7.1.5.arch1-2
    The Linux kernel and modules
local/linux-api-headers 7.1-1
    Kernel headers sanitized for use in userspace
local/linux-firmware 20260622-1
    Firmware files for Linux - Default set
local/linux-firmware-amdgpu 20260622-1
    Firmware files for Linux - Firmware for AMD Radeon GPUs
local/linux-firmware-atheros 20260622-1
    Firmware files for Linux - Firmware for Qualcomm Atheros WiFi and Bluetooth adapters
local/linux-firmware-broadcom 20260622-1
    Firmware files for Linux - Firmware for Broadcom and Cypress network adapters
local/linux-firmware-cirrus 20260622-1
    Firmware files for Linux - Firmware for Cirrus Logic audio devices
local/linux-firmware-intel 20260622-1
    Firmware files for Linux - Firmware for Intel devices
local/linux-firmware-mediatek 20260622-1
    Firmware files for Linux - Firmware for MediaTek and Ralink devices
local/linux-firmware-nvidia 20260622-1
    Firmware files for Linux - Firmware for NVIDIA GPUs and SoCs
local/linux-firmware-other 20260622-1
    Firmware files for Linux - Unsorted firmware for various devices
local/linux-firmware-radeon 20260622-1
    Firmware files for Linux - Firmware for ATI Radeon GPUs
local/linux-firmware-realtek 20260622-1
    Firmware files for Linux - Firmware for Realtek devices
local/linux-firmware-whence 20260622-1
    Firmware files for Linux - WHENCE file (vendor licenses)
local/linux-headers 7.1.5.arch1-2
    Headers and scripts for building modules for the Linux kernel
local/man-pages 6.18-1
    Linux man pages
local/mdadm 4.6-2
    A tool for managing/monitoring Linux md device arrays, also known as Software RAID
local/multipath-tools 0.15.0-1
    Multipath tools for Linux (including kpartx)
local/ndctl 85-1
    Utility library for managing the libnvdimm (non-volatile memory device) sub-system in the Linux kernel
local/net-tools 2.10-3
    Configuration tools for Linux networking
local/pacman-mirrorlist 20260610-1
    Arch Linux mirror list for use by pacman
local/pps-tools 1.0.3-2
    LinuxPPS user-space tools
local/python-brltty 6.9.1-3
    Braille display driver for Linux/Unix - Python bindings
local/python-evdev 1.9.3-1
    Python bindings for the Linux input subsystem
local/python-hidraw-pure 1.2-2
    Pythonic binding for Linux's hidraw ioctls
local/python-ioctl-opt 1.3.1-1
    Pythonified Linux asm-generic/ioctl.h
local/tlp 1.10.2-1
    Linux Advanced Power Management
local/torbrowser-launcher 0.3.9-1
    Securely and easily download, verify, install, and launch Tor Browser in Linux
local/udftools 2.3-3
    Linux tools for UDF filesystems and DVD/CD-R(W) drives
local/util-linux 2.42.2-1
    Miscellaneous system utilities for Linux
local/util-linux-libs 2.42.2-1
    util-linux runtime libraries
local/v4l-utils 1.32.0-2
    Userspace tools and conversion library for Video 4 Linux
local/virt-install 5.1.0-4
    Command line tool for creating new KVM , Xen, or Linux container guests using the libvirt hypervisor

Links
journalctl (GitLab Snippet)

Last edited by sample1693 (2026-08-08 03:28:34)

seth · 2026-08-06 06:30:14

The device is there and has a carrier - NM fails to obtain a lease via dhcp

Aug 05 22:58:11 desktop dnsmasq-dhcp[2652]: DHCP, IP range 192.168.122.2 -- 192.168.122.254, lease time 1h

https://wiki.archlinux.org/title/Dnsmasq#DHCP_server
Why do you enable this? You likely create a rogue dhcp server this way.

sample1693 · 2026-08-06 21:11:35

seth wrote:

The device is there and has a carrier - NM fails to obtain a lease via dhcp
Aug 05 22:58:11 desktop dnsmasq-dhcp[2652]: DHCP, IP range 192.168.122.2 -- 192.168.122.254, lease time 1h
https://wiki.archlinux.org/title/Dnsmasq#DHCP_server
Why do you enable this? You likely create a rogue dhcp server this way.

Not sure why this is being logged in the journal. I don't have the dnsmasq service enabled. I think I may have installed it for libvirtd and QEMU.

$ sudo systemctl status dnsmasq
[sudo] password for aakash: 
○ dnsmasq.service - dnsmasq - A lightweight DHCP and caching DNS server
     Loaded: loaded (/usr/lib/systemd/system/dnsmasq.service; disabled; preset: disabled)
     Active: inactive (dead)
       Docs: man:dnsmasq(8)

seth · 2026-08-06 21:21:12

Please post the output of

find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f

sample1693 · 2026-08-06 22:06:50

seth wrote:

Please post the output of

find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f

$ find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f
autovt@.service                          | system
bluetooth.service                        | bluetooth.target.wants
dbus-org.bluez.service                   | system
dbus-org.freedesktop.nm-dispatcher.service | system
dbus-org.freedesktop.timesync1.service   | system
display-manager.service                  | system
fwupd-refresh.timer                      | timers.target.wants
getty@tty1.service                       | getty.target.wants
gnome-keyring-daemon.socket              | sockets.target.wants
libvirtd-admin.socket                    | sockets.target.wants
libvirtd-ro.socket                       | sockets.target.wants
libvirtd.service                         | multi-user.target.wants
libvirtd.socket                          | sockets.target.wants
mullvad-daemon.service                   | multi-user.target.wants
NetworkManager-wait-online.service       | network-online.target.wants
NetworkManager.service                   | multi-user.target.wants
p11-kit-server.socket                    | sockets.target.wants
pcscd.socket                             | sockets.target.wants
pipewire-pulse.socket                    | sockets.target.wants
pipewire-session-manager.service         | user
pipewire.socket                          | sockets.target.wants
remote-fs.target                         | multi-user.target.wants
speech-dispatcher.socket                 | sockets.target.wants
systemd-timesyncd.service                | sysinit.target.wants
systemd-userdbd.socket                   | sockets.target.wants
tlp.service                              | multi-user.target.wants
ufw.service                              | multi-user.target.wants
virtlockd-admin.socket                   | sockets.target.wants
virtlockd.socket                         | sockets.target.wants
virtlogd-admin.socket                    | sockets.target.wants
virtlogd.socket                          | sockets.target.wants
wireplumber.service                      | pipewire.service.wants
xdg-user-dirs.service                    | graphical-session-pre.target.wants

seth · 2026-08-06 22:28:57

Ah,

Aug 05 22:58:10 desktop systemd[1]: Starting libvirt legacy monolithic daemon...
Aug 05 22:58:11 desktop systemd[1]: Started libvirt legacy monolithic daemon.
Aug 05 22:58:11 desktop dnsmasq[2652]: read /var/lib/libvirt/dnsmasq/default.addnhosts - 0 names
Aug 05 22:58:11 desktop dnsmasq-dhcp[2652]: read /var/lib/libvirt/dnsmasq/default.hostsfile

What if you disable them and only explicitly/manually start them after you obtained a lease?

sample1693 · 2026-08-06 22:49:52

seth wrote:

Ah,

Aug 05 22:58:10 desktop systemd[1]: Starting libvirt legacy monolithic daemon...
Aug 05 22:58:11 desktop systemd[1]: Started libvirt legacy monolithic daemon.
Aug 05 22:58:11 desktop dnsmasq[2652]: read /var/lib/libvirt/dnsmasq/default.addnhosts - 0 names
Aug 05 22:58:11 desktop dnsmasq-dhcp[2652]: read /var/lib/libvirt/dnsmasq/default.hostsfile

What if you disable them and only explicitly/manually start them after you obtained a lease?

Do you mean libvirtd or dnsmasq? The dnsmasq service is already disabled, but libvirtd isn't. Does libvirtd also manage networking? I was under the impression that it only handled virtualization.

seth · 2026-08-06 22:56:57

libvirt - dnsmasq is an optional dependency for network connectivity, see https://wiki.archlinux.org/title/Libvirt#Server (ie. you can also just uninstall dnsmasq for testing this)
The server shoudl™ only listen on virbr0 but you've dhcp issues and there's an unexpected dhcp server - that's a bit too much on the nose to not check whether it's the origin of the problem

sample1693 · 2026-08-07 02:32:54

seth wrote:

libvirt - dnsmasq is an optional dependency for network connectivity, see https://wiki.archlinux.org/title/Libvirt#Server (ie. you can also just uninstall dnsmasq for testing this)
The server shoudl™ only listen on virbr0 but you've dhcp issues and there's an unexpected dhcp server - that's a bit too much on the nose to not check whether it's the origin of the problem

Unfortunately, even after disabling the libvirtd service, I'm still experiencing the same issue.

journalctl (GitLab Snippet)

seth · 2026-08-07 04:20:29

mullvad or netfilter ( nft or iptables)

nft list ruleset # don't install
iptables -nvL # either of those if they're not present

If there's neither (dhcp is ports 67/68) the last thing to check would be dhclient/dhcpcd (ie. a bug in NM's internal dhcp client), https://wiki.archlinux.org/title/Networ … HCP_client

Otherwise you'd have to look at the other side of the connection (ie. the dhcp server, likely your router/modem combo - tried to reboot that?)
You can also check

sudo nmap --script broadcast-dhcp-discover

Edit: malcontent has shown up unrelated before - https://bbs.archlinux.org/viewtopic.php … 4#p2300034
It might be the gnomiuses determined network to be in need of parental approval by default…

Last edited by seth (2026-08-07 04:23:48)

sample1693 · 2026-08-08 03:27:18

seth wrote:

mullvad or netfilter ( nft or iptables)
nft list ruleset # don't install
iptables -nvL # either of those if they're not present
If there's neither (dhcp is ports 67/68) the last thing to check would be dhclient/dhcpcd (ie. a bug in NM's internal dhcp client), https://wiki.archlinux.org/title/Networ … HCP_client
Otherwise you'd have to look at the other side of the connection (ie. the dhcp server, likely your router/modem combo - tried to reboot that?)
You can also check
sudo nmap --script broadcast-dhcp-discover
Edit: malcontent has shown up unrelated before - https://bbs.archlinux.org/viewtopic.php … 4#p2300034
It might be the gnomiuses determined network to be in need of parental approval by default…

Wow! Disabling the Mullvad service seems to have fixed the issue! I can't recall whether I started experiencing this problem before or after I installed Mullvad, but either way, thank you so much. At least now I know that a networking related service can interfere with Ethernet connectivity.

seth · 2026-08-08 05:51:10

mullvad explicitly starts before the network-online.target so likely is supposed to take control over the dhcp request and probably adds some wireguard related netfilter rules, did you https://wiki.archlinux.org/title/Mullva … figuration ?

sample1693 · 2026-08-08 15:21:11

seth wrote:

mullvad explicitly starts before the network-online.target so likely is supposed to take control over the dhcp request and probably adds some wireguard related netfilter rules, did you https://wiki.archlinux.org/title/Mullva … figuration ?

I had installed Mullvad to test something on my machine. I think it would be better to set it up on my router instead, so that my entire home network can take advantage of it. Thanks for sharing the documentation!

Arch Linux

#1 2026-08-06 03:26:12

[SOLVED] Recurring Ethernet Issues Following Updates

#2 2026-08-06 06:30:14

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#3 2026-08-06 21:11:35

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#4 2026-08-06 21:21:12

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#5 2026-08-06 22:06:50

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#6 2026-08-06 22:28:57

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#7 2026-08-06 22:49:52

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#8 2026-08-06 22:56:57

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#9 2026-08-07 02:32:54

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#10 2026-08-07 04:20:29

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#11 2026-08-08 03:27:18

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#12 2026-08-08 05:51:10

Re: [SOLVED] Recurring Ethernet Issues Following Updates

#13 2026-08-08 15:21:11

Re: [SOLVED] Recurring Ethernet Issues Following Updates

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