Unknown transport protocol: b'OS'

[Darksice (Thomas Amaro)]

CMK version: 2.3.0p3.cre
OS version: Rocky Linux release 9.4 (Blue Onyx)

Error message: Unknown transport protocol: b’OS’

I got this error message only on Rocky 8.X host on every other OS it works perfectly fine (it also works fine on Rocky 9.X). Error shows up after the upgrade on 2.3.

Output of “cmk --debug -vvn hostname”: (If it is a problem with checks or plugins)

Don’t really know if it’s relevant but when I look at a host that works I can see :

Detected transport protocol: TransportProtocol.TLS
Reading data from agent via TLS socket
Reading data from agent
Detected transport protocol: TransportProtocol.PLAIN

Where on Rocky 8.X there is only :

Detected transport protocol: TransportProtocol.TLS
Reading data from agent via TLS socket
Reading data from agent

And at the end of the cmk --debug command it says :

[agent] Unknown transport protocol: b'OS'(!!), [piggyback] Success (but no data found for this host), Missing monitoring data for all plugins(!)

If you need any other information, feel free to ask.

Thomas

[chauhan_sudhir]

Have you looked at the agent output ?
Maybe some section from a custom agent plugin or local is producing this string?

Is it possible to reproduce ?

[Darksice (Thomas Amaro)]

Hello, sorry for the late reply, I haven’t had much time.

I don’t see anything in the agent output and there is no custom control on this host. I’ll keep looking.

I had the problem on a Centos7 so I don’t think it’s only on Rocky 8 as I said.

I don’t have much more information at the moment.

[Darksice (Thomas Amaro)]

Interestingly, if I stop the cmk-agent-ctl-daemon service and delete the TLS record, it works after xinetd is enabled.