Try to see if the CPU and interface details are in the plugin output. On the check_mk server, login as the site user and do a telnet to a Windows server with the missing details on port 6556
telnet <windowshost> 6556
Or, if you don’t have telnet:
nc -v <windowshost> 6556
Then see if you have sections <<<winperf_if>>> and <<<winperf_processor>>>. If you don’t the issue is most likely at the Windows host; otherwise at the check_mk server.
Yes, I do see the winperf_if and winperf_processor section in the output. What could be possible missing in check_mk server ? as few servers do show the CPU and Interface counters properly.
Ok, can you compare those to the output of a server that does work? Should be similar. If they are, maybe an automatic refresh of the services in check_mk will fix the issue.
If that doesn’t work, can you please post the output of the telnet command?