Nagios Support Forum

Hello,
I followed the instructions under:

https://assets.nagios.com/downloads/nag ... ios-XI.pdf

and want to monitor the updates on a windows 2019 server.

The script is working on the machine itself.

Command: "./check_nrpe -H [IP of the windows system]" gives me the output "seem to be doing fine"

Now I followed the instructions and run the command "./check_nrpe -H <Remote Windows IP address> -t 120 -p 5666 -c check_updates" with root on the Nagios VM, and get this output:

CHECK_NRPE: Invalid packet version received from server.
CHECK_NRPE: Receive header underflow - only 0 bytes received (4 expected).

The nsclient log says:
2020-06-23 16:14:15: error:c:\source\nscp\include\socket/connection.hpp:149: Failed to send data: The file handle supplied is not valid

NSCLIENT: NSCP-0.4.4.23-x64
Nagios XI 5.7.1 on a virtual machine

No firewall in between
Same IP-Net / Same VLAN

I already changed the timeout in the nsclient.ini, but problem still exists...

Any suggestions?
Or do other ways exist to get alarms, if there are windows updates ready or not installed probably?

This may be because of an incompatibility between versions of your check plugin and agent. You could add the -2 option to the check command to force it to use a version 2 packet. Please see the following linked knowledge base article for more information on this.
NOT SUPPORTED PACKETS

Is the address SSL encrypted? ( HTTP or HTTPS ) If not, you may want to use the -n option so that it doesn't try to make an encrypted connection.

Can you please send us ( PM ) or post your *.ini file and/or system profile? You can download the profile by navigating to System Profile under System Config on the left pane > and clicking the Download Profile button on that page.

That's the output for -2 / -n option

[root@XXXXXX libexec]# ./check_nrpe -2 -n -H XXX.XXX.XXX.XXX -t 120 -p 5666 -c check_updates
CHECK_NRPE: Receive header underflow - only 0 bytes received (4 expected).
[root@XXXXXX libexec]#


log from nsclient:

2020-06-24 06:20:45: error:c:\source\nscp\include\socket/connection.hpp:243: Failed to establish secure connection: unknown protocol: 252
2020-06-24 06:20:53: error:c:\source\nscp\include\socket/connection.hpp:243: Failed to establish secure connection: unknown protocol: 252
2020-06-24 06:20:53: error:c:\source\nscp\include\socket/connection.hpp:243: Failed to establish secure connection: unknown protocol: 252
2020-06-24 06:22:01: error:c:\source\nscp\include\socket/connection.hpp:243: Failed to establish secure connection: unknown protocol: 252
2020-06-24 06:23:04: error:c:\source\nscp\include\socket/connection.hpp:149: Failed to send data: The file handle supplied is not valid
2020-06-24 06:24:49: error:c:\source\nscp\include\socket/connection.hpp:149: Failed to send data: The file handle supplied is not valid

I send a PM with the two files.

Thanks

It appears that your agent is trying to use an encrypted connection, which means that we should not use the -n option. check_nrpe must be using version three or later protocol then. Apparently the main difference between version two and three of NRPE is that the packet size was limited to 1024 bytes.

You can force NSClient++ to accept larger packet sizes by defining the payload length as follows in the NRPE section of your nsclient.ini file.

changed the ini / restarted the client but it didn't worked

[root@xxxxx libexec]# ./check_nrpe -2 -H xxxxxxxxx -t 120 -p 5666 -c check_updates
CHECK_NRPE: Receive header underflow - only 0 bytes received (4 expected).

I apologize if I wasn't more clear, but I believe you should remove the -2 flag on the command. Can you please try it again without the -2 flag?

Feel free to send me ( PM ) the *.ini file and your system profile so that I can take a look. You can download the profile by navigating to System Profile under System Config on the left pane > and clicking the Download Profile button on that page.

CHECK_NRPE: Invalid packet version received from server.
CHECK_NRPE: Receive header underflow - only 0 bytes received (4 expected).


I'll send the ini and profile shortly

I'll send the ini and profile shortly

Noted