Port 6556 is used by systemd

[Michaeljoechl (Michael)]

CMK version: 2.1p11
OS version: Debian 11

Hello,

I am Using Checkmk 2.1 and i am Monitoring 9 Hosts. Most of them are about an year old and Debian 11. Before Updating to 2.1 everything works fine. Now there is the Message: „Host is registered for TLS but not using it“

I Unterstand the Problem and know that ist possible to Use the Legacy Mode.

But i am looking for an better Solution

ss -tulpn | grep 6556
tcp LISTEN 0 4096 *:6556 : users:((“systemd”,pid=1,fd=55))

So i See that systemd is listening on the Port, if i kill the Process and Install the Agent everything is Fine, and i can Connect it to my Checkmk Server.
After a Restart Systemd is using it again.

Is it possible to Tell systemd NOT to Listen on this Port?
Or is the only Solution to Use the Legacy Mode?

Greetings Form Ostfriesland
Michael

[BSBS]

When upgrading from 2.0 or earlier, try purging the agent package and reinstalling it.
That fixed an update-related problem for me, but I don’t remember if it was that one

[Michaeljoechl (Michael)]

Oh okay thank you I will try later

[Michaeljoechl (Michael)]

I tried it, but it doesnt work
Also if i Uninstall check-MK-Agent is systemd allways in Use of 6556 (also After reboot)

[BSBS]

ok, we gotta dive a little deeper then.

grep -Rw 6556 /etc

This might point to xinetd config or it might point to a systemd socket unit, or potentially both
Can you post the result?

You can ignore /etc/check_mk/xinetd-service-template.cfg btw. That comes with the 2.1 agent package and is expected.

[Michaeljoechl (Michael)]

Ahhhhh i got it haha

Just uninstall the Agent, and delete all Check-Mk* in /etc/systemd/system

Reinstall the New Agent and it worked

Thank you

[BSBS]

check if those belonged to some other package