Issue Email Security - dnsutils not found

[Atramasis]

Server operating system version

Ubuntu 22.04.2

Plesk version and microupdate number

18.0.51 Update #1

I use the free version of Email Security. on top of Config Check there is this warning:
"Plesk Email Security could not execute the local DNS caching check due to a missing system utility. Please install bind-utils (CentOS/Red Hat Linux) or dnsutils (Ubuntu/Debian derivatives) over SSH to enable this functionality!"

I have the latest version of dnsutils installed (1:9.18.12-0ubuntu0.22.04.1). I think my local DNS caching is set up correctly, but still it would be nice if this warning would be gone. How can I correct it?

 

[Kulturmensch]

What is the content of /etc/resolv.conf?

 

[Atramasis]

It's a link to /run/systemd/resolve/stub-resolv.conf

Content:

nameserver 127.0.0.53
options edns0 trust-ad
search .

And /etc/systemd/resolved.conf content:

DNS=127.0.0.1 85.214.7.22 81.169.163.106 81.169.148.34

 

[Kulturmensch]

If you can manage to get this content for /etc/resolv.conf

nameserver 127.0.0.1
nameserver 127.0.0.53
options edns0 trust-ad
search .

then this would satisfy Plesk E-Mail-Security:

One possibility is to modify /run/systemd/resolve/stub-resolv.conf this way but depending on your OS and the configuration of your server this file become overwritten with the default content on reboot or in worth case every minute by systemd. The reboot problem can be solved by a cron job the 2nd problem I am facing by myself and didn`t find a satisfying solution up to now.