Arch Linux

SJ_work

Member

Registered: 2026-05-07

Posts: 2

Wired lan regular disconnect

Hii

I cant figure this out and i need help troubleshooting this.

I have a Lenovo T480s that is connected to a USB-C monitor Dell P3221D. To the monitor i have attached a USB-RJ45 adapter (i have tried multiple) and a LAN cable.

I am running arch ofc and Mate on top.

When i connect everything. Everything works.
If i leave the it connected for 24h (sleep is disabled) it shows it is connected but no data seems to flow. No webpage loads etc.
If i do a soft disconnect and reconnect. The situation remains the same most of the time. Sometimes a hard disconnect is required. (i assume it has something to do with the length of time between disconnect and reconnect, but hard disconnect works every time)

How to even begin to troubleshoot something like this? I know there is a bug somewhere. I can smell it.
This issue did not exist on your favorite operating system... Windows.

Advice required.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,838

Re: Wired lan regular disconnect

What do you understand "soft" and "hard" *connects to be?

If i leave the it connected for 24h (sleep is disabled) it shows it is connected but no data seems to flow. No webpage loads etc.

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

Also the output of

ip a; ip r; lsusb -tvnn

24h eerily sounds like a dhcp lease timeout, ie. your router disconnects you but typically that gets conveyed when obtaining the lease and the network managing service should™ renew the lease in time.
Then there's oc the "To the monitor i have attached a USB-RJ45 adapter"
Do you have the same problem w/ the rj45
* plugged directly into the notebook
* dongle attached directly to the notebook
?

How to even begin to troubleshoot something like this?

System journal.

Ceterum censeo:

This issue did not exist on your favorite operating system... Windows.

3rd link below. Mandatory.
Disable it (it's NOT the BIOS setting!) and reboot windows and linux twice for voodo reasons.

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How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

SJ_work

Member

Registered: 2026-05-07

Posts: 2

Re: Wired lan regular disconnect

Strangely enough... ever since i made this post i have not had this issue.
Since i can not even replicate this myself i think this can be considered solved. At least for now.

Thank you for the knowledge and help.

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 75,838

Re: Wired lan regular disconnect

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.

Feel free to remove that tag and bump the thread in case the issue re-emerges.

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How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc