• Download the Installer for 32bit Windows
• Download the Installer for 64bit Windows

Install NSClient++

IF you already have NSClient++ installed on this computer then you can skip this step, as you can enable the modules as described in the steps further on.

• Run the installer
  
• The welcome page appears
  
• Click Next
• Tick the box I accept the terms in the License Agreement
  
• Click Next
• Click Custom
• Accept the default ini file location
• Click Next
• Tick the box Install sample configuration
• Tick the box Allow users to write config file
• Click Next
• Allowed hosts
• Leave this blank as it's not required for NSCA
  
• NSClient Password
• Leave this blank as it's not required for NSCA
  
• Modules to load (tick the following):
• Enable common check plugins
• Enable NSCA client
  
• Click Next
• Click Install
• Wait for NSClient++ to install
• When finished click Finish

Configure NSClient++

There are a couple of final settings to change in the config file.

• Open a command prompt
  
• Type cd "\Program Files\NSClient++\" and press Enter
• Type nscp settings --activate-module NSCAClient --add-defaults and press Enter
• This may prompt you for permission
• This adds some more defaults to the config file
  
• Type notepad "C:\Program Files\NSClient++\nsclient.ini" and press Enter
• This opens the config file in Notepad and the options are explained in more detail next
  

• This section enables all the modules required to make NSCA work.
  
• [/modules]
CheckSystem = enabled
NSCAClient = enabled
Scheduler = enabled
  
  
• In this section, the only thing worth mentioning here is that if you want to change the actual hostname that is reported to the NSCA server, you and define it here instead of using auto (this will use the windows computers name).
• [/settings/NSCA/client]
channel = NSCA
hostname = auto


• This is where you define the destination NSCA server and the required parameters. The encryption and password must be the same on the NSCA server.
  
• [/settings/NSCA/client/targets/default]
address = 10.25.5.2
encryption = 1
password = Passw0rd


• This is where you define how often you want NSClient++ to run the checks and then submit the check results to the NSCA server.
  
• [/settings/scheduler/schedules/default]
interval = 1m


• Here are the actual checks being performed and the results for each of these checks will be submitted to the NSCA server.
• [/settings/scheduler/schedules]
CPU Load = checkCPU warn=80 crit=90 time=5m time=1m time=30s
Memory Usage = checkMem MaxWarn=80% MaxCrit=90% ShowAll=long type=physical type=virtual type=paged type=page
  
  
  
• To make it clear, the NSCA server will receive two service check results.
• The first one will be for the service named CPU Load
• NSClient++ uses checks build into it's CheckSystem module, specfically checkCPU
• The second one will be for the service named Memory Usage
• NSClient++ uses checks build into it's CheckSystem module, specfically checkMem

• Once you've made any required changes, Save and Close the nsclient.ini file
  

Start NSClient++

• Open the Run dialog (Windows Key + R)
  
• Type services.msc and press Enter
• This opens the services management console
• Find NSClient++ service
• Right click it and select Restart
• Wait for the service to start
• Close the services manangement console when service is started

Observe Nagios Log

• SSH to your Nagios NSCA server
  
• Type tail -f /usr/local/nagios/var/nagios.log and press Enter
• You should see data like:
  
• [1419048801] EXTERNAL COMMAND: PROCESS_SERVICE_CHECK_RESULT;DC01;CPU Load;0;OK CPU Load ok.|'5m'=0%;80;90 '1m'=1%;80;90 '30s'=2%;80;90
[1419048801] Warning:  Passive check result was received for service 'CPU Load' on host 'DC01', but the host could not be found!
[1419048801] Error: External command failed -> PROCESS_SERVICE_CHECK_RESULT;DC01;CPU Load;0;OK CPU Load ok.|'5m'=0%;80;90 '1m'=1%;80;90 '30s'=2%;80;90
[1419048801] External command error: Command failed

[1419048806] EXTERNAL COMMAND: PROCESS_SERVICE_CHECK_RESULT;DC01;Memory Usage;0;OK: physical memory: Total: 2G - Used: 675M (32%) - Free: 1.34G (68%), virtual memory: Total: 8T - Used: 212M (0%) - Free: 8T (100%), paged bytes: Total: 4G - Used: 693M (16%) - Free: 3.32G (84%), page file: Total: 4G - Used: 693M (16%) - Free: 3.32G (84%)|'physical memory %'=32%;80;90 'physical memory'=675.266M;1638.044;1842.799;0;2047.555 'virtual memory %'=0%;80;90 'virtual memory'=211.672M;6710886.3;7549747.087;0;8388607.875 'paged bytes %'=16%;80;90 'paged bytes'=692.559M;3276.087;3685.598;0;4095.109
[1419048806] Warning:  Passive check result was received for service 'Memory Usage' on host 'DC01', but the host could not be found!
[1419048806] Error: External command failed -> PROCESS_SERVICE_CHECK_RESULT;DC01;Memory Usage;0;OK: physical memory: Total: 2G - Used: 675M (32%) - Free: 1.34G (68%), virtual memory: Total: 8T - Used: 212M (0%) - Free: 8T (100%), paged bytes: Total: 4G - Used: 693M (16%) - Free: 3.32G (84%), page file: Total: 4G - Used: 693M (16%) - Free: 3.32G (84%)|'physical memory %'=32%;80;90 'physical memory'=675.266M;1638.044;1842.799;0;2047.555 'virtual memory %'=0%;80;90 'virtual memory'=211.672M;6710886.3;7549747.087;0;8388607.875 'paged bytes %'=16%;80;90 'paged bytes'=692.559M;3276.087;3685.598;0;4095.109
[1419048806] External command error: Command failed
  
  
• This confirms that NSClient++ is working
• The errors are simply because there are no services called "CPU Load" or "Memory Usage" for the host localhost
• NOTE: Once you add service objects to Nagios for these Passive check results, they will no longer be logged in nagios.log unless you define this in your core nagios.cfg.

What about the Host itself?

When NSCA receives these check results, they are targeted at a host, because all services in Nagios must belong to a host. You can actually submit a check result for the host object itself , simply add this to nsclient.ini:

[/settings/scheduler/schedules]
host_check = CheckOK "Everything is working fine"


An you will see these results in nagios.log:

[1419048991] EXTERNAL COMMAND: PROCESS_HOST_CHECK_RESULT;DC01;0;Everything is working fine
[1419048991] Warning:  Passive check result was received for host 'DC01', but the host could not be found!
[1419048991] Error: External command failed -> PROCESS_HOST_CHECK_RESULT;DC01;0;Everything is working fine
[1419048991] External command error: Command failed

More Examples

Different checks require different modules in NSClient++ to be enabled:

• Disks
• [/modules]
CheckDisk = enabled

[/settings/scheduler/schedules]
Drive Usage = CheckDriveSize MinWarn=10% MinCrit=5% CheckAll FilterType=FIXED

  
• WMI Queries
• [/modules]
CheckWMI = enabled

[/settings/scheduler/schedules]
Operating System Version = CheckWMI "Query=Select Version,Caption from win32_OperatingSystem"