Arch Linux

Cator Canulis

Member

Registered: 2018-03-23

Posts: 13

netctl fails because "interface already up"

Cheers,

I installed the most recent version of arch on my server yesterday.

Despite the obvious disadvantages I decided to hook the server up via wifi (so I can place it whereever I want).

I installed dhcpcd, netctl, dialog (for wifi-menu) and wpa_supplicant.

Connecting to wifi worked during installation but not in the installed system.

ntctl won't configure the interface because it's already up an configured (but by what?).

Issuing

    ip link set wlp2s0 down

and then

    netctl start wifi2

works. On the next reboot, it's the same problem. How can I set up netctl configuring the wifi interface persistently?

Thanks in advance

Markus

Slithery

Administrator

From: Norfolk, UK

Registered: 2013-12-01

Posts: 5,776

Re: netctl fails because "interface already up"

systemctl list-unit-files --state=enabled

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CarbonChauvinist

Member

Registered: 2012-06-16

Posts: 413

Website

Re: netctl fails because "interface already up"

You more than likely have multiple services trying to manage your network. What's the output of

systemctl list-unit-files --state=enabled

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Cator Canulis

Member

Registered: 2018-03-23

Posts: 13

Re: netctl fails because "interface already up"

The output was
- autovt.service
- dhcpcd.service
- getty0.service
- netctl.service
- sshd.service
- remote-fs.target

I enabled netctl. But there is no difference wether it is enabled or not.

CarbonChauvinist

Member

Registered: 2012-06-16

Posts: 413

Website

Re: netctl fails because "interface already up"

This link from the netctl wiki appears to match your issue, try the steps outlined there if you haven't already.

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"the wind-blown way, wanna win? don't play"

loqs

Member

Registered: 2014-03-06

Posts: 18,294

Re: netctl fails because "interface already up"

You have dhcpcd.service and netctl.service both attempting to control the interface.

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 20,346

Re: netctl fails because "interface already up"

The output was
- autovt.service
- dhcpcd.service
- getty0.service
- netctl.service
- sshd.service
- remote-fs.target

I enabled netctl. But there is no difference wether it is enabled or not.

No, it was not.   Please post actual output when it is requested. 
Regardless, carefully read loqs' post.

Last edited by ewaller (2019-11-05 03:02:15)

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Cator Canulis

Member

Registered: 2018-03-23

Posts: 13

Re: netctl fails because "interface already up"

Thanks for the Link CarboChauvinist. This solution worked for me already. Unfortunately it does not survive reboot. Also "ForceConnect=yes" doesn't solve the problem.

Oddly enough, I disabled all network related services that I could find (dhcpcd, netctl and also wpa_supplicant). The error message about the failed netctl service remained.

I solved it for the time beeing by creating a systemd-unit that shuts the interface down and then reenables it, in the late boot stages. But it doesn't seem like the correct way to solve this issue.

@ewaller: Sorry, but I cant copy paste from a command line only machine without network access. Typing it in seemed impractical.

Cator Canulis

Member

Registered: 2018-03-23

Posts: 13

Re: netctl fails because "interface already up"

You have dhcpcd.service and netctl.service both attempting to control the interface.

I had a look at /etc/dhcpcd.conf but couldn't find any setting that would indicate that dhcpcd is configuring wlp2s0.

seth

Member

Registered: 2012-09-03

Posts: 61,147

Re: netctl fails because "interface already up"

The unconditional dhcpcd service (w/o @something) seeks to control all interfaces.

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Cator Canulis

Member

Registered: 2018-03-23

Posts: 13

Re: netctl fails because "interface already up"

How can this be prevented? I'm completely new to "manuel networking". If necessary I will dig deeper through the wiki pages, but maybe it's just a very simple command or setting in some conf-file...

Last edited by Cator Canulis (2019-11-05 10:34:06)

loqs

Member

Registered: 2014-03-06

Posts: 18,294

Re: netctl fails because "interface already up"

Choose one network management service to use on the system and stop plus disable the other.