Ethernet really unstable - connecting and disconnecting

HI everyone !

I have an infuriating problem - Ethernet constantly connects and disconnects on Manjaro

I’ve ruled out cable or hardware problems.
This system has a hardswitch (not dual booting) where I can hardswitch between Manjaro, Win10 and Ubuntu - same motherboard, separate switched drives - shared ethernet adaptor and cables.

On ethernet : Manjaro is fast but very unstable and constantly loses the ethernet connection, other connections are fast and stable.

Here’s my INXI :

System:
  Kernel: 6.0.0-1-MANJARO arch: x86_64 bits: 64 compiler: gcc v: 12.2.0
    parameters: BOOT_IMAGE=/boot/vmlinuz-6.0-x86_64
    root=UUID=17480e2f-6383-4189-8c7d-ca2681b5aefd rw quiet apparmor=1
    security=apparmor udev.log_priority=3
  Desktop: KDE Plasma v: 5.25.5 tk: Qt v: 5.15.6 wm: kwin_x11 vt: 1 dm: SDDM
    Distro: Manjaro Linux base: Arch Linux
Machine:
  Type: Desktop Mobo: ASUSTeK model: M5A97 R2.0 v: Rev 1.xx
    serial: <superuser required> BIOS: American Megatrends v: 2603
    date: 06/26/2015
CPU:
  Info: model: AMD FX-6350 bits: 64 type: MT MCP arch: Piledriver level: v2
    built: 2012-13 process: GF 32nm family: 0x15 (21) model-id: 2 stepping: 0
    microcode: 0x6000852
  Topology: cpus: 1x cores: 6 smt: enabled cache: L1: 288 KiB desc: d-6x16
    KiB; i-3x64 KiB L2: 6 MiB desc: 3x2 MiB L3: 8 MiB desc: 1x8 MiB
  Speed (MHz): avg: 1825 high: 3600 min/max: 1400/3900 boost: enabled
    scaling: driver: acpi-cpufreq governor: schedutil cores: 1: 1400 2: 3600
    3: 1708 4: 1446 5: 1400 6: 1400 bogomips: 46976
  Flags: avx ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm
  Vulnerabilities:
  Type: itlb_multihit status: Not affected
  Type: l1tf status: Not affected
  Type: mds status: Not affected
  Type: meltdown status: Not affected
  Type: mmio_stale_data status: Not affected
  Type: retbleed mitigation: untrained return thunk; SMT vulnerable
  Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via
    prctl
  Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer
    sanitization
  Type: spectre_v2 mitigation: Retpolines, IBPB: conditional, STIBP:
    disabled, RSB filling, PBRSB-eIBRS: Not affected
  Type: srbds status: Not affected
  Type: tsx_async_abort status: Not affected
Graphics:
  Device-1: NVIDIA GP104 [GeForce GTX 1070] vendor: eVga.com. driver: nvidia
    v: 515.76 alternate: nouveau,nvidia_drm non-free: 515.xx+ status: current
    (as of 2022-10) arch: Pascal code: GP10x process: TSMC 16nm built: 2016-21
    pcie: gen: 2 speed: 5 GT/s lanes: 16 bus-ID: 01:00.0 chip-ID: 10de:1b81
    class-ID: 0300
  Device-2: Logitech Webcam C310 type: USB driver: snd-usb-audio,uvcvideo
    bus-ID: 2-1.2.1:46 chip-ID: 046d:081b class-ID: 0102 serial: <filter>
  Display: x11 server: X.Org v: 21.1.4 compositor: kwin_x11 driver: X:
    loaded: nvidia gpu: nvidia display-ID: :0 screens: 1
  Screen-1: 0 s-res: 3840x2160 s-dpi: 157 s-size: 621x341mm (24.45x13.43")
    s-diag: 708mm (27.89")
  Monitor-1: HDMI-0 res: 3840x2160 hz: 60 dpi: 157
    size: 621x341mm (24.45x13.43") diag: 708mm (27.89") modes: N/A
  OpenGL: renderer: NVIDIA GeForce GTX 1070/PCIe/SSE2 v: 4.6.0 NVIDIA 515.76
    direct render: Yes
Audio:
  Device-1: AMD SBx00 Azalia vendor: ASUSTeK driver: snd_hda_intel v: kernel
    bus-ID: 2-1.2.1:46 chip-ID: 046d:081b bus-ID: 00:14.2 class-ID: 0102
    chip-ID: 1002:4383 class-ID: 0403 serial: <filter>
  Device-2: NVIDIA GP104 High Definition Audio vendor: eVga.com.
    driver: snd_hda_intel v: kernel pcie: gen: 2 speed: 5 GT/s lanes: 16
    bus-ID: 01:00.1 chip-ID: 10de:10f0 class-ID: 0403
  Device-3: Logitech Webcam C310 type: USB driver: snd-usb-audio,uvcvideo
  Sound API: ALSA v: k6.0.0-1-MANJARO running: yes
  Sound Server-1: JACK v: 1.9.21 running: no
  Sound Server-2: PulseAudio v: 16.1 running: yes
  Sound Server-3: PipeWire v: 0.3.58 running: yes
Network:
  Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
    vendor: ASUSTeK P8 series driver: r8168 v: 8.050.03-NAPI modules: r8169
    pcie: gen: 1 speed: 2.5 GT/s lanes: 1 port: d000 bus-ID: 02:00.0
    chip-ID: 10ec:8168 class-ID: 0200
  IF: enp2s0 state: down mac: <filter>
  Device-2: Realtek RTL8812AE 802.11ac PCIe Wireless Network Adapter
    vendor: ASUSTeK driver: rtl8821ae v: kernel pcie: gen: 1 speed: 2.5 GT/s
    lanes: 1 port: c000 bus-ID: 05:00.0 chip-ID: 10ec:8812 class-ID: 0280
  IF: wlp5s0 state: down mac: <filter>
  Device-3: Realtek RTL8153 Gigabit Ethernet Adapter type: USB driver: r8152
    bus-ID: 2-1.2.2:47 chip-ID: 0bda:8153 class-ID: 0000 serial: <filter>
  IF: enp0s19f2u1u2u2 state: up speed: 1000 Mbps duplex: full mac: <filter>
Drives:
  Local Storage: total: 2.94 TiB used: 96.57 GiB (3.2%)
  SMART Message: Unable to run smartctl. Root privileges required.
  ID-1: /dev/sda maj-min: 8:0 vendor: Samsung model: SSD 870 QVO 1TB
    size: 931.51 GiB block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s
    type: SSD serial: <filter> rev: 1B6Q scheme: MBR
  ID-2: /dev/sdb maj-min: 8:16 vendor: Kingston model: SA400S37240G
    size: 223.57 GiB block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s
    type: SSD serial: <filter> rev: J4.3 scheme: MBR
  ID-3: /dev/sdc maj-min: 8:32 vendor: Hitachi model: HDS721010CLA332
    size: 931.51 GiB block-size: physical: 512 B logical: 512 B speed: 3.0 Gb/s
    type: HDD rpm: 7200 serial: <filter> rev: A3EA scheme: GPT
  ID-4: /dev/sdd maj-min: 8:48 model: SATA3 240GB SSD size: 223.57 GiB
    block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s type: SSD
    serial: <filter> rev: 0A0 scheme: MBR
  ID-5: /dev/sde maj-min: 8:64 vendor: Seagate model: ST3500620AS
    size: 465.76 GiB block-size: physical: 512 B logical: 512 B speed: 3.0 Gb/s
    type: HDD rpm: 7200 serial: <filter> rev: HP21 scheme: MBR
  ID-6: /dev/sdf maj-min: 8:80 vendor: Seagate model: ST3250820AS Q
    size: 232.89 GiB block-size: physical: 512 B logical: 512 B speed: 3.0 Gb/s
    type: N/A serial: <filter> rev: E scheme: GPT
Partition:
  ID-1: / raw-size: 931.51 GiB size: 915.81 GiB (98.31%) used: 96.57 GiB
    (10.5%) fs: ext4 dev: /dev/sda1 maj-min: 8:1
Swap:
  Alert: No swap data was found.
Sensors:
  System Temperatures: cpu: 23.6 C mobo: N/A gpu: nvidia temp: 43 C
  Fan Speeds (RPM): N/A gpu: nvidia fan: 0%
Info:
  Processes: 205 Uptime: 21m wakeups: 3 Memory: 15.52 GiB used: 2.14 GiB
  (13.8%) Init: systemd v: 251 default: graphical tool: systemctl Compilers:
  gcc: 12.2.0 alt: 11 clang: 14.0.6 Packages: 1826 pm: pacman pkgs: 1802
  libs: 361 tools: pamac pm: flatpak pkgs: 14 pm: snap pkgs: 10 Shell: Zsh
  v: 5.9 default: Bash v: 5.1.16 running-in: konsole inxi: 3.3.22

I’d really appreciate some help to troubleshoot

many thanks !

Hello,

Do you have tlp installed? Either remove it, since is a Desktop PC, disable mac address randomization and disable IPv6 …

you have two Ethernet interfaces and it seems you use the slower one, the enp0s19f2u1u2u2 which seems to be an USB-to-Ethernet adapter. Is this correct? How is the stability with the on-board eth?

BTW: for network issues always include info about the network, e.g., “ip route”, “ip link” and “netstat -c -i ” (for some seconds).

HP

Hi bogdancovaciu

I understand tlp is a laptop power management tool - and since this is a desktop, I’ve removed.

thank you for the advice

Hi hape,

yes this is correct.

So I have my desktop with Manjaro and a work laptop on Windows 11.
To avoid constantly connecting and disconnecting cables - and to be able to share a monitor, keyboard and mouse I use a KVM 2 port switch, leave everything connected and switch on the KVM to swap from Desktop to Laptop and use the same peripherals.

The Dell notebook laptop does not have an ethernet port, and has only 1 USB-A port, so the only way I can connect successfully to the KVM switch, is to use one of the KVM USB ports with a USB hub, then connect ethernet cable with a USB ethernet adaptor (USB 3.0 to Giganet supposedly) into the KVM switch.

ip route :

default via 192.168.0.1 dev enp0s19f2u1u2u2 proto dhcp src 192.168.0.21 metric 100 
192.168.0.0/24 dev enp0s19f2u1u2u2 proto kernel scope link src 192.168.0.21 metric 100 

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 fq_codel state DOWN mode DEFAULT group default qlen 1000
    link/ether f8:32:e4:b9:86:3a brd ff:ff:ff:ff:ff:ff
3: wlp5s0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
    link/ether f6:aa:a5:b6:5c:ff brd ff:ff:ff:ff:ff:ff permaddr a8:5e:45:db:9a:72
4: enp0s19f2u1u2u2: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 00:e0:4c:6b:d8:5c brd ff:ff:ff:ff:ff:ff

netstat -c -i

Kernel Interface table
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184853      0      4 0         68347      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184866      0      4 0         68360      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184875      0      4 0         68371      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184883      0      4 0         68378      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184889      0      4 0         68384      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184894      0      4 0         68389      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184900      0      4 0         68396      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184907      0      4 0         68402      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184912      0      4 0         68407      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184923      0      4 0         68417      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184931      0      4 0         68425      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184956      0      4 0         68450      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
Iface             MTU    RX-OK RX-ERR RX-DRP RX-OVR    TX-OK TX-ERR TX-DRP TX-OVR Flg
enp0s19f2u1u2u2  1500   184965      0      4 0         68458      0      0      0 BMRU
enp2s0           1500        0      0      0 0             0      0      0      0 BMU
lo              65536       18      0      0 0            18      0      0      0 LRU
^Z
zsh: suspended  netstat -c -i

thanks for you reply

J

Ok, routing and interface entries look good. Regarding the netstat output, you had almost no traffic in your timeframe. I wanted to know if netstat showed some errors. Maybe you repeat the netstat and download something during the measurement and tell us if some errors (RX_ERR or TX-ERR) can be seen. Additionally i propose to run a ‘ping 8.8.8.8’ for some seconds to see the round trip times and losses.

And pls. explain how you notice that the connection breaks. Is it in the browser?

Maybe someone else has ideas if the USB setup could be a problem, i’m not an expert here. ‘lsusb’ may give some first info.

HP

Hi Hape, thanks for your reply.

Well - an update I think : Working at home today - on my Work Dell laptop on Win11- for the first time that I recall, real Ethernet connection problems.
That was an International MSTeams meeting with 10 people - and it was embarrassingly bad !!! :slight_smile:

That makes me think it’s a hardware issue - because that’s both Manjaro & Win11 on the same USB adapter and KVM giving issues.

At the moment I’m on ethernet directly into the desktop on Manjaro (no USB adaptor) and no KVM and so far, stable.
I’ll monitor that for the weekend - and hopefully that will confirm its not my ethernet cables or sockets or the desktop hardware - or Manjaro or a driver problem… it’s probably the USB3.0 to Gigabyte Ethernet adaptor - or more likely the 4 port USB hub into the KVM.

The really annoying thing is that the Dell Notebook doesn’t have an RJ45 port - and my wifi just isn’t man enough for 10 people MSTeams International meetings apparently.

I’m so sorry for taking your time - this seems to be a hardware issue after all !

I’ll mark as closed if i don’t have any sudden disconnects by Sunday evening.

Many thanks !

Johnny

No problem, i sometimes love to solve such puzzles :slight_smile:

Can you see errors in the netstat output of the USB device?

10 people in a MSTeams should be a problem for the WLAN as MS somewhere on their servers mixes the video. Maybe look at the task manager to see how much traffic gets produced.

I sometimes also use USB-to-Eth adapters under Linux and never had problems. So it might be a defect.

HP