NSClient++ rejects connection or fails to send info

Question

I'm trying to get to work some active checks on Windows endpoint machines, NSClient++ works just fine with my Windows servers but when it comes to checking any endpoint the only response I get is either could not fetch information from server or CRITICAL - Socket timeout. I've checked my firewall, the endpoints' firewall and AV protection, the config files on the Nagios server and the nsclient.ini file, this is the content of my ini file:

; Undocumented section
[/modules]

; NRPE server - A simple server that listens for incoming NRPE connection and handles them.
NRPEServer = enabled

; NSClient server - A simple server that listens for incoming NSClient (check_nt) connection and handles them. Although NRPE is the preferred method NSClient is fully supported and can be used for simplicity or for compatibility.
NSClientServer = enabled


; Undocumented section
[/settings/default]

; ALLOWED HOSTS - A comaseparated list of allowed hosts. You can use netmasks (/ syntax) or * to create ranges.
allowed hosts = 192.168.x.x

[/settings/NRPE/server]

; Undocumented key
verify mode = none

; Undocumented key
insecure = true

The full file can be found here.

Any guidance would be very helpful and appreciated.

Answer 1

Is the allowed hosts value correct for the NSClient listener? This is a common mistake as you need to "whitelist" who is allowed to call it up and run commands.