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#1 2020-11-20 20:49:55

Soyman
Member
Registered: 2017-06-23
Posts: 24

[SOLVED] Intermittent connection falures on wired connection

I have a desktop computer that is connected to a router via a wire.
Regularly when I try to go to a webpage on firefox it immediately fails and tells me that it can't connect to the server.
If I try to refresh a few times I always get to the website shortly.

I have done some troubleshooting and have found that I'm using the dhcpcd service.
The connection seems to shut of completely, i.e. I can't even reach my router.
The connection only drops for about 3-5 seconds. I can't tell if anything(like load) is triggering the connection loss.
It drops fairly reliably with around 10-20 seconds between connection loss.

I have been using Arch for some years on my laptop and just made the jump on my desktop.
I managed to set the wifi up on the laptop without much hassle years ago and have hardly touched anything network related since then.
I had a ~5 year old arch install on my desktop that had been unused for ~4 years.
I had to do some tricks with a liveUSB to be able to update such an unmaintained install. It seems to be fine besides this single thing.
Not sure if it's relevant but decided to mention it anyways.
This issue is not on the windows side.

Last edited by Soyman (2020-11-20 23:34:06)

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#2 2020-11-20 21:22:53

Soyman
Member
Registered: 2017-06-23
Posts: 24

Re: [SOLVED] Intermittent connection falures on wired connection

So I kept troubleshooting and tried disabling the dhcpcd@enp0s25 service.
The intention was to disable the connection to try using netctl with some potential solution I found.
That however seems to have fixed the issue.

The problem is that I have no idea what is managing my connection.
I am also slightly concerned because the roundtrip time to my router(connected with a short cable) is fuctuating from 0.3 ms up to 4 ms and occasionally jumps to 20 ms.

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#3 2020-11-20 21:30:12

teckk
Member
Registered: 2013-02-21
Posts: 518

Re: [SOLVED] Intermittent connection falures on wired connection

The problem is that I have no idea what is managing my connection.

systemctl list-unit-files

Run only 1 network manager. 2 or more will conflict.

Also:
man journalctl
man systemctl

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#4 2020-11-20 21:35:53

seth
Member
Registered: 2012-09-03
Posts: 49,985

Re: [SOLVED] Intermittent connection falures on wired connection

@teckk, we figured that list-unit-files skips units - among them several dhcpcd ones. See https://bbs.archlinux.org/viewtopic.php?id=256156

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

prints a nicely formatted version of (hopefully actually) all services.

@Soyman
Also post the output of "lspci", there're some threads about issues w/ rtl8168 chips.

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#5 2020-11-20 23:33:28

Soyman
Member
Registered: 2017-06-23
Posts: 24

Re: [SOLVED] Intermittent connection falures on wired connection

teckk wrote:

Run only 1 network manager. 2 or more will conflict.

I thought that I was running only one but looking at journalctl would have shown me the root of that issue, thanks for that tip.

seth wrote:

...prints a nicely formatted version of (hopefully actually) all services.

I ran that command and found a dhcpcd@eth0 service running.
I don't know that I have a eth0 interface on this computer but I disabled the service.
Disabling it didn't seem to change anything.
I think I'll just mark this as solved as the main problem is gone and I'm not even sure this 2-4 ping with spikes of 15 is anything to worry about or waste your time with.
Thanks for all your help!

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