Ethernet Connecting and disconnecting

Rince91 · 2025-08-12 11:26:58

Any help with this would be greatly appreciated!

System details:
/ \ │  distro │ Arch Linux x86_64
/ ,, \ │  kernel │ Linux 6.15.8-arch1-2
/ | | \ │  wm │ Hyprland 0.50.1 (Wayland)
/_-'' ''-_\ │  term │ kitty 0.42.2
│  shell │ zsh 5.9
│ ? cpu │ AMD Ryzen 7 9800X3D (16) @ 5.27 GHz

My ethernet connection keeps connecting and disconnecting. I think it is because there are conflicts between network manager and systemd.

 find /etc/systemd -type l -exec test -f {} \; -print
/etc/systemd/user/default.target.wants/xdg-user-dirs-update.service
/etc/systemd/user/sockets.target.wants/pipewire-pulse.socket
/etc/systemd/user/sockets.target.wants/p11-kit-server.socket
/etc/systemd/user/sockets.target.wants/pipewire.socket
/etc/systemd/user/pipewire-session-manager.service
/etc/systemd/user/pipewire.service.wants/wireplumber.service
/etc/systemd/system/sockets.target.wants/systemd-userdbd.socket
/etc/systemd/system/sockets.target.wants/systemd-networkd.socket
/etc/systemd/system/mullvad-daemon.service.wants/mullvad-early-boot-blocking.service
/etc/systemd/system/dbus-org.freedesktop.resolve1.service
/etc/systemd/system/dbus-org.freedesktop.timesync1.service
/etc/systemd/system/bluetooth.target.wants/bluetooth.service
/etc/systemd/system/dbus-org.freedesktop.ratbag1.service
/etc/systemd/system/multi-user.target.wants/mullvad-daemon.service
/etc/systemd/system/multi-user.target.wants/lactd.service
/etc/systemd/system/multi-user.target.wants/systemd-networkd.service
/etc/systemd/system/multi-user.target.wants/NetworkManager.service
/etc/systemd/system/multi-user.target.wants/cpu_probe.service
/etc/systemd/system/multi-user.target.wants/remote-fs.target
/etc/systemd/system/timers.target.wants/fstrim.timer
/etc/systemd/system/dbus-org.bluez.service
/etc/systemd/system/dbus-org.freedesktop.network1.service
/etc/systemd/system/dbus-org.freedesktop.nm-dispatcher.service
/etc/systemd/system/network-online.target.wants/NetworkManager-wait-online.service
/etc/systemd/system/network-online.target.wants/systemd-networkd-wait-online.service
/etc/systemd/system/sysinit.target.wants/systemd-timesyncd.service
/etc/systemd/system/sysinit.target.wants/systemd-network-generator.service
/etc/systemd/system/sysinit.target.wants/systemd-resolved.service
/etc/systemd/system/getty.target.wants/getty@tty1.service
/etc/systemd/system/display-manager.service

Here is an example out of my journalctl:

Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1105] device (enp9s0): carrier: link connected
Aug 12 12:15:32 redders kernel: r8169 0000:09:00.0 enp9s0: Link is Up - 1Gbps/Full - flow control off
Aug 12 12:15:32 redders systemd-networkd[14354]: enp9s0: Gained carrier
Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1106] device (enp9s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1110] policy: auto-activating connection 'Wired connection 1' (3def323a-12a6-3cdf-8f04-00b0fad64023)
Aug 12 12:15:32 redders systemd-networkd[14354]: Foreign process 'NetworkManager[14401]' changed sysctl '/proc/sys/net/ipv6/conf/enp9s0/disable_ipv6' from '0' to '1', conflicting with our setting to '0'.
Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1112] device (enp9s0): Activation: starting connection 'Wired connection 1' (3def323a-12a6-3cdf-8f04-00b0fad64023)
Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1113] device (enp9s0): state change: disconnected -> prepare (reason 'none', managed-type: 'full')
Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1114] device (enp9s0): state change: prepare -> config (reason 'none', managed-type: 'full')
Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1116] device (enp9s0): state change: config -> ip-config (reason 'none', managed-type: 'full')
Aug 12 12:15:32 redders systemd-networkd[14354]: Foreign process 'NetworkManager[14401]' changed sysctl '/proc/sys/net/ipv6/conf/enp9s0/disable_ipv6' from '0' to '1', conflicting with our setting to '0'.
Aug 12 12:15:32 redders NetworkManager[14401]: <info>  [1754997332.1118] dhcp4 (enp9s0): activation: beginning transaction (timeout in 45 seconds)
Aug 12 12:15:33 redders systemd-networkd[14354]: enp9s0: Gained IPv6LL
Aug 12 12:15:34 redders NetworkManager[14401]: <info>  [1754997334.1179] dhcp4 (enp9s0): state changed new lease, address=192.168.0.195, acd pending
Aug 12 12:15:34 redders NetworkManager[14401]: <info>  [1754997334.2656] dhcp4 (enp9s0): state changed new lease, address=192.168.0.195
Aug 12 12:15:34 redders NetworkManager[14401]: <info>  [1754997334.2768] device (enp9s0): state change: ip-config -> ip-check (reason 'none', managed-type: 'full')
Aug 12 12:15:34 redders systemd[1]: Starting Network Manager Script Dispatcher Service...
Aug 12 12:15:34 redders systemd[1]: Started Network Manager Script Dispatcher Service.
Aug 12 12:15:34 redders NetworkManager[14401]: <info>  [1754997334.3034] device (enp9s0): state change: ip-check -> secondaries (reason 'none', managed-type: 'full')
Aug 12 12:15:34 redders NetworkManager[14401]: <info>  [1754997334.3034] device (enp9s0): state change: secondaries -> activated (reason 'none', managed-type: 'full')
Aug 12 12:15:34 redders NetworkManager[14401]: <info>  [1754997334.3036] device (enp9s0): Activation: successful, device activated.
Aug 12 12:15:34 redders steam[1424]: [2025-08-12 12:15:34] Background update loop checking for update. . .
Aug 12 12:15:34 redders steam[1424]: [2025-08-12 12:15:34] Downloading manifest: https://client-update.fastly.steamstatic.com/steam_client_ubuntu12
Aug 12 12:15:34 redders NetworkManager[14401]: <info>  [1754997334.4204] policy: set 'Wired connection 1' (enp9s0) as default for IPv4 routing and DNS
Aug 12 12:15:34 redders steam[1424]: [2025-08-12 12:15:34] Manifest download: send request
Aug 12 12:15:34 redders steam[1424]: [2025-08-12 12:15:34] Manifest download: waiting for download to finish
Aug 12 12:15:34 redders systemd-networkd[14354]: enp9s0: Lost carrier
Aug 12 12:15:34 redders kernel: r8169 0000:09:00.0 enp9s0: Link is Down

I have tried disabling networkmanager and only using systemd but this leaves me completely disconnected and cannot use the ethernet connection.

I have tried vice versa, using only networkmanager and disabling systemd, this has intermittent success.

I have also tried moving to a different driver from r8169 > r8168, this had a few hours of stability then became intermittent again.

I decided to use timeshift to restore to a snapshot back in July, this stabilised my Ethernet connection, but when i then try to login to uwsm-managed (hyprland) the display session doesn't load and my monitor receives no signal and turns off. I can launch into the standard hyprland session though.

Am i best just performing a fresh install?

seth · 2025-08-12 12:22:17

I have tried vice versa, using only networkmanager and disabling systemd, this has intermittent success.

What does "intermittent" mean here, exactly?

example out of my journalctl

Disable networkd, reboot, wait for a connection to drop out and then please post

ip a
sudo journalctl -b | curl -F 'file=@-' 0x0.st # this will upload the journal to 0x0.st and hand you a link

mullvad-daemon.service could be an obvious pot. cause for "internet not working" even if the carrier and lease are fine…

Rince91 · 2025-08-12 13:38:05

Disabling networkd seems to have stablised things, no drops since disabled.

https://0x0.st/8Coh.txt

Rince91 · 2025-08-12 14:40:18

Unfortunately its still occurring but a lot less frequently now.

Ethernet will stay up for a while (1hr or so) then flap.

https://0x0.st/8CXa.txt

seth · 2025-08-12 18:30:20

Aug 12 14:47:13 redders NetworkManager[744]: <info>  [1755006433.7699] device (enp9s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Aug 12 15:28:35 redders NetworkManager[744]: <info>  [1755008915.9143] device (enp9s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Aug 12 15:31:24 redders NetworkManager[744]: <info>  [1755009084.3665] device (enp9s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Aug 12 15:31:44 redders NetworkManager[744]: <info>  [1755009104.9335] device (enp9s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Aug 12 15:32:46 redders NetworkManager[744]: <info>  [1755009166.3080] device (enp9s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')
Aug 12 15:37:44 redders NetworkManager[744]: <info>  [1755009464.5424] device (enp9s0): state change: unavailable -> disconnected (reason 'carrier-changed', managed-type: 'full')

Make sure the cable is tightly seated on both ends.
Do you have another cable?

Rince91 · 2025-08-12 21:12:19

Yeah its not the cable,its been stable for the last 8 hours now with no issue. So think disabling only the networkd service has fixed it. I was disabling other systemd network service previously like "resolver", but have left them running now and all seems to be working.

Thanks for the help

seth · 2025-08-13 05:31:28

Yeah its not the cable

… famous last words…

"systemd-resolved" might break your DNS resolutions but carrier changes are the cable - at "best" power management.

Please always remember to mark resolved threads by editing your initial posts subject - so others will know that there's no task left, but maybe a solution to find.
Thanks.

Arch Linux

#1 2025-08-12 11:26:58

Ethernet Connecting and disconnecting

#2 2025-08-12 12:22:17

Re: Ethernet Connecting and disconnecting

#3 2025-08-12 13:38:05

Re: Ethernet Connecting and disconnecting

#4 2025-08-12 14:40:18

Re: Ethernet Connecting and disconnecting

#5 2025-08-12 18:30:20

Re: Ethernet Connecting and disconnecting

#6 2025-08-12 21:12:19

Re: Ethernet Connecting and disconnecting

#7 2025-08-13 05:31:28

Re: Ethernet Connecting and disconnecting

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