How to disable systemd-resolved in Ubuntu

README.md

How to disable systemd-resolved in Ubuntu

Stages

• Disable and stop the systemd-resolved service:

    sudo systemctl disable systemd-resolved.service
    sudo systemctl stop systemd-resolved
  

• Then put the following line in the [main] section of your /etc/NetworkManager/NetworkManager.conf:

    dns=default
  

• Delete the symlink /etc/resolv.conf

    rm /etc/resolv.conf
  

• Restart network-manager

    sudo service network-manager restart
    or
    sudo systemctl restart NetworkManager.service
  

Sources

• https://askubuntu.com/questions/907246/how-to-disable-systemd-resolved-in-ubuntu

This is wrong, instead of dns=none it should be dns=default

Yes, I don't know what happened at the time of writing, but currently I have dns=default, thanks for warning!

what is dns=default tho? I use 1.1.1.1 on my resolv.conf and want to keep using that

@tweakunwanted you can see the documentation of NetworkManager. If you don't want /etc/resolv.conf to be changed, assign dns=none.

Thanks for fixing my VPN wish I'd find this 2 hours before.

Any idea how to do this on centos8 - even systemctl mask systemd-resolved doesn't fix it, none of the above does either and /etc/resolv.conf isn't a symlink on centos8, dns=none is the default

This just saved my butt. For some reason resolved just decided to stop working. After two hours of pain killing resolved did the trick. Yet one more reason why I hate systemd. Just want it do die a painful death.

Just a nit: I find it odd that you use service to restart NetworkManager and not systemctl since the former is just a compatibility wrapper around the latter.

this has started causing

sudo service network-manager restart
sudo: unable to resolve host ubuntu-18-04: Resource temporarily unavailable

Worked like a charm on Kubuntu 20.04.1 LTS.

Just a note in case people need to undo these instructions:

The symlink for /etc/resolv.conf points to ../run/systemd/resolve/stub-resolv.conf

/etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf

This was helpful, I was trying to configure vhosts using network manager and the missing piece was deleting the symlink from systemd. Thanks!

I don't know why but ever since returning to the office (I'm on WIFI because someone let the cable fall behind the desk) I lose DNS resolution. It works for a few minutes then fails. This seems to have fixed it. Thanks!

dns=none worked for me even after restarting the network-manager. However, dns=default set the nameserver to 127.0.0.53after restarting it.

I got network-manager: unrecognized service on ubuntu18.04, what should I do?
try to fix the chromium-based brower bug
[1116/153011.148474:ERROR:file_io_posix.cc(144)] open /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq: No such file or directory (2)
[1116/153011.148719:ERROR:file_io_posix.cc(144)] open /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq: No such file or directory (2)

@zhengxunWu1

sudo service network-manager restart

Did not work for me with Ubuntu 21.10. I used the command from the source of this gist.

sudo systemctl restart NetworkManager

Thanks, this resolved VPN-issued DNS servers not being used in Docker containers for me on Pop_OS! 21.10.

If anyone wants to do it extra quick I wrote a little playbook:

# apt/yum install ansible, then:
curl -L https://bit.ly/3MqjHO0 > disable-systemd-resolved.yaml
ansible-galaxy collection install community.general
ansible-playbook -v disable-systemd-resolved.yaml

@thekoma: I'd advise everyone to no to use URL shorteners when it comes to blind code execution on user's machines. The content that hides behind that URL could change at any moment in time and could become malicious.

It's not blind. I'm not piping into bash. I've just shortened the gist url which is marked in the first statement.
But if you prefer: https://gist.githubusercontent.com/thekoma/b0d28f96b0384d9c630c244e216a6e03/raw/b9a2be01d6d0a7521c2102a7ea2c0bb74c0365c1/disable-systemd-resolved.yaml

We did not have NetworkManager service installed (fresh ubuntu 20.04). We kept the systemd-resolved service running and changed the /etc/resolv.conf symlink to use another resolv.conf file.

Default symlink was this:

/etc/resolv.conf  ->  ../run/systemd/resolve/stub-resolv.conf

We changed it to:

/etc/resolv.conf  ->  ../run/systemd/resolve/resolv.conf

This means we don't use a 127.0.0.53 cached resolver, but we keep using the generated resolv.conf file from the systemd-resolved service. Which is overwritten/managed by netplan.

Original issue

We are running applications in docker which could not connect to any internally hosted applications on their local DNS name. Docker documentation about DNS:

By default, a container inherits the DNS settings of the host, as defined in the /etc/resolv.conf configuration file [..] If the container cannot reach any of the IP addresses you specify, Google’s public DNS server 8.8.8.8 is added, so that your container can resolve internet domains.

We discovered using journalctl -xeu docker that docker was using google's DNS, so we figured that docker was not able to reach the configured DNS service. Which is correct. The /etc/resolv.conf file which was using nameserver 127.0.0.53 also for docker, resolves to the docker container and not the guest host.

Following these steps on a fresh Ubuntu 22.10 install completely breaks dns

Local dns servers are perfectly functional, Ubuntu sees them and they show in network config, but it refuses to use them, what gives?

Don't forget to add back the resolv.conf:

echo 'search example.com' > /etc/resolv.conf
echo 'nameserver 1.1.1.1' >> /etc/resolv.conf
echo 'nameserver 1.0.0.1' >> /etc/resolv.conf

systemd-resolvwhatever broke after upgrading ubuntu, and it was easier to just switch back to the Thing That Always Worked than to try to figure it out.

Following these steps on a fresh Ubuntu 22.10 install completely breaks dns

Local dns servers are perfectly functional, Ubuntu sees them and they show in network config, but it refuses to use them, what gives?

How do you solve the DNS issue for 22.10 please?

root@www::> systemctl disable systemd-resolved
root@www::> systemctl stop systemd-resolved
root@www::> rm -f /etc/resolv.conf
root@www::> cat < /etc/resolv.conf
nameserver 9.9.9.9
nameserver 8.8.8.8
nameserver 1.1.1.1
EOF
root@www:~:> reboot

Why not just rename instead of remove?

mv /etc/resolv.conf /etc/resolv.conf.del