DNS not working

Hi,

I am lost with DNS configuration. I searched everywhere but I can´t find a working solution.

Situtation is, that /etc/resolv.conf is always resetted to default when rebooting the OMV:

root@intrepid:~# cat /etc/resolv.conf
# Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8)
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN
nameserver 127.0.0.1

When I enter my DNS Server manually in the file, it works. But next reboot -> defaults.

Whatever I enter in GUI can´t be seen in /etc/resolv.conf which is linked to /etc/resolvconf/run/resolv.conf.

I tried to run omv-firstaid to fix that, but dind´t work. I have set an static IPv4 adress with DNS server and IPv6 to DHCP.

When I reboot the machine systemd-resolved is dead:

root@intrepid:~# systemctl status systemd-resolved.service
● systemd-resolved.service - Network Name Resolution
Loaded: loaded (/lib/systemd/system/systemd-resolved.service; enabled; vendor
Drop-In: /lib/systemd/system/systemd-resolved.service.d
└─resolvconf.conf
Active: inactive (dead)
Docs: man:systemd-resolved.service(8)
https://www.freedesktop.org/wiki/Software/systemd/resolved
https://www.freedesktop.org/wiki/Software/systemd/writing-network-con
https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-cl

If I start the service by hand it is running.

I also tried to run dpkg-reconfigure resolvconf. Didn´t help also.

I have no more clue how to fix that.

Can anyone help?

I think I have a solution.

I deinstalled resolvconf and DNS behaves normal now

This is a very good question.

The system runs since OMV 3 and has always been upgraded. Perhaps something from the past?

I also installed pihole directly on OMV, because I have no clue how I can use IPv6 with macvlan in Docker

Maybe it was pihole?

I deinstalled pihole

Many thanks for your support, again!