DNS Check not working after update to 1.6

I have problems with my DNS checks after updating from cmk 1.50p21cee to 1.6.0p7cee.
I have 2 checks for each DNS server in our net:

  • One is checking against an external domain (check_mk_active-dns!-H ‘www.yahoo.com’ -s ‘$HOSTADDRESS$’ -> check_dns -H ‘www.yahoo.com’ -s’)
  • One is checking against an internal domain (check_mk_active-dns!-H ‘dah-fs.arthrose.de’ -s ‘$HOSTADDRESS$’ -a ‘’ -> check_dns -H ‘domain.internal.org’ -s’)
    The check against the external domain is okay, the internal check reports ‘Plugin timed out while executing system call’
    On check_mk 1.5 both checks are okay.

Any ideas to solve the problem?

WATO > Host & Service Parameters > Active Checks > Check DNS Service

Yes, that was the way I created the check!

I solved the Problem now. It seems to be a problem with different updates.

Hi @deutarthrosehilfe, how exactly did you solve this? I seem to have the same issue. I’m on 1.6.0.p8cre

Hi, I installed all system updates on the check_mk servers and restarted the dns servers. After that, the checks run without errors.
It was a very strange thing: A call from commandline was executed with the correct answer, but within the check_mk-system I get a error.


Thanks for the response, I had to disable DNS checks because it didn’t work or me, furthermore I have no access to our DNS servers so couldn’t follow all steps. I’m hoping it’s going to work again, once new version of check_mk gets released.


Hi there
we have the same problem.

Check_mk version 1.6.p10.cee runs on an Ubuntu 18.04 LTS.
Is there already a solution to the problem?