NSClient++ (nscp)

NSClient++ (nscp) aims to be a simple yet powerful and secure monitoring daemon. It was built for Nagios/Icinga, but nothing in the daemon is Nagios/Icinga specific and it can be used in many other scenarios where you want to receive/distribute check metrics.

The daemon has 3 main functions:

• Allow a remote machine (monitoring server) to request commands to be run on this machine (the monitored machine) which return the status of the machine.
• Submit the same results to a remote (monitoring server).
• Take action and perform tasks.

NSClient++ can be found at: http://nsclient.org

Documentation can be found at: http://docs.nsclient.org

Extending NSClient++

NSClient++ is designed to be open ended and allow you to customize it in any way you design thus extensibility is a core feature.

• ExternalScripts responds to queries and are executed by the operating system and the results are returned as-is. This is generally the simplest way to extend NSClient++ as you can utilize whatever infrastructure or skill set you already have.
• LuaScripts are internal scripts which runs inside NSClient++ and performs various tasks and/or responds to queries. This is the best option if you want to allow the script to run on any platform with as little infrastructure as possible.
• PythonScripts are internal scripts which runs inside NSClient++ and performs various tasks and/or responds to queries. Python is an easy and powerful language but it requires you to also install python which is often not possible on server hardware.
• .Net modules similar to Native modules below but written on the dot-net platform. This allows you to write components on top of the large dot-net ecosystem.
• Modules are native plugins which can extend NSClient++ in pretty much any way possible. This is probably the most complicated way but gives you the most power and control.

Talking to NSClient++

Since NSClient++ is meaningless by itself it also supports a lot of protocols to allow it to be used by a lot of monitoring solutions.

• NRPE (Nagios Remote plugin Executor) is a Nagios centric protocol to collect remote metrics.
• NSCA (Nagios Service Check Acceptor) is a Nagios centric protocol for submitting results.
• NSCP is the native NSClient++ protocol (still under development)
• dNSCP is a high performance distributed version of NSCP for high volume traffic.
• NRDP is a replacement for NSCA.
• check_mk is a protocol utilized by the check_mk monitoring system.
• Syslog is a protocol primarily designed for submitting log records.
• Graphite allows you do real-time graphing.
• SMTP is more of a toy currently.

Supported OS/Platform

NSClient++ should run on the following operating systems:

• Windows: From NT4 SP5 up to Windows 2012R2 and Windows 8.1
• Linux: Debian, Centos and Ubuntu (and possibly others as well)
• Win32, x64 as well as various Linux hardware as well.

Building NSClient++

NSClient++ is built using CMake and Visual Studio 2022. You can find detailed instructions for building locally in the build.md file.