Wired network: random droputs and OS freezes

I’ll do my best to provide required details. If the info below is insufficient please let me know what else you may find helpful. If I cannot solve this problem I will have to jump off Manjaro to either OpenSuSE tumbleweed or MX Linux. Manjaro Deepin is my 1st Arch based distro, but had to chg to KDE due to its unreliability starting last year. MX Linux is great, but not a rolling release. I hate the hassle of OS upgrades which tend to break things I’ve installed after the OS.

After reading this thread, I set IPv6 to “ignore”, since I didn’t see a “disable” method option under network config. That thread also suggested turning off MAC randomization so I will try that next. I’m doubtful that is causing the lockups but may be related to breaking the network connection. Is the randomization performed multiple times while a connection is open or only when one is first established? If the later I don’t see how that could explain random disconnects.

Here is some general background:

1- I have this problem with all kernels, but it’s far worse with 5.x versions.

2- I have seen it with Manjaro versions 19 and 20, deepin, xfce and kde variants.

3- I have eliminated all hardware, vpn and isp variables, it’s definitely a an OS issue. Could be in Debian root, so I installed the latest OpenSuSE Tumbleweed and I do not see the problem with that OS .

4- I have another system with an old Fedora 23 kernel acting as a proxy to other Debian VMs and don’t see the problem there either.

5- The major symptom I’m seeing is random network connection dropouts, which often trigger a system lockup requiring reboot. At the very least it kills my VPN connection. System lockup or user session lockups are also occurring randomly but not very frequently. This seems to indicate a low level bug with a driver or in the kernel.

Hardware: Asus Ultrabook UX490. Uses a USB-C (Thunderbolt) dongle for wired network. I have used 2 different dongles, both stable no problem under OpenSuSE.

From KDE System Info:
Operating System: Manjaro Linux
KDE Plasma Version: 5.19.5
KDE Frameworks Version: 5.73.0
Qt Version: 5.15.0
Kernel Version: 5.8.6-1-MANJARO
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz
Memory: 15.5 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620

  1. Try a CAT-6 cable first! (<100m)

  2. Even though it works under OpenSuSE and/or Windows: Try another cable first: CAT-5E would be the minimum)

  3. Trust me: try another cable before you do anything else! :stuck_out_tongue_winking_eye: :crazy_face:

  4. Which one exactly?


I can’t say I follow the logic you used to suggest that.

Admittedly, I don’t know everything, which is why I posted the question here. If by some small chance a network cable was the cause, after days of testing under other Operating Systems and on another computer I believe the problem would surface and that hasn’t happened. It seems highly improbable a faulty network cable would cause a total system lockup either.

I will give you credit in suggesting to disable IPv6. Although I’m not sure the “Ignore” setting is actually disabling IPv6 (seems like an unusual choice of words to use compared with all others I’ve seen to change network options), it may be the issue, as I haven’t had a network failure all day.

Unfortunately this morning I’ve already had one dropout, but not willing to say it’s cause is on my machines or network. For now it seems the IPv6 change seems to be impacting the problem.

Thanks for the suggestion!

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Different experience, different quick and dirty solutions. In my experience, 90% of all IT problems can be solved by changing the cable or the driver. :grin:

If you’re sure about your cables being in excellent health, but you still have hiccups it might be beneficial to try using half duplex on your current cable and see if that alleviates 100% of said hiccups:

nmcli connection show

pick your Ethernet connection (mine is called Wired connection 1, yours will be different) and:

nmcli connection edit Wired\ connection\ 1

(Please note \ to escape space characters) and change the following parameters, but start with auto-negotiation (obviously set to no) and duplex (set to half):

802-3-ethernet.speed:                   0
802-3-ethernet.duplex:                  --
802-3-ethernet.auto-negotiate:          no


All 3 were already set as you suggested above. I tried to change wake on lan using property values of no and ignore. “No” fails and ignore is accepted, but a subsequent query shows it to be set to “default” (it’s not relevant to the issue here).

Only do this:

if you still have hiccups.