## Nagios Addons

The following is a description of various "addons" that are available for Nagios. These and other addons can be obtained from the downloads page on the Nagios website (www.nagios.org).

Index

nrpe - Daemon and plugin for executing plugins on remote hosts
nsca - Daemon and client program for sending passive check results across the network

nrpe - Daemon and plugin for executing plugins on remote hosts

Author: | Me
Overview: | Allows you to execute plugins on remote hosts in a relatively easy and transparent manner.

Files:

check_nrpe | - Plugin used to send execution requests to the nrpe agent on the remote host
nrpe | - Agent that runs on the remote host and processes plugin execution requests
nrpe.cfg | - Configuration file for the remote host agent

Description:

This addon is designed to provide a way for executing plugins on a remote host. The check_nrpe plugin runs on the Nagios host and is used to send plugin execution requests to the nrpe agent on the remote host. The nrpe agent will then run an appropriate plugins on the remote host and return the plugin output and return code to the check_nrpe plugin on the Nagios host. The check_nrpe plugin then passes the remote plugin's output and return code back to Nagios as if it were its own. This allows for a rather transparent method of executing plugins on remote hosts. The nrpe agent can either be run as a standalone daemon or as a service under inetd.

Notes:

- When running in daemon mode, the nrpe agent authenticates plugin execution requests by doing a rudimentary comparison of the IP address of the calling host against a list of allowed IP addresses in the configuration file.
- When running under inetd, TCP wrappers can be employed to restrict access to the nrpe agent

nsca - Daemon and client program for sending passive check results across the network

Author: | Me
Overview: | Allows you to submit passive service checks results to another server on the network that is running Nagios.

Files:

nsca | - Daemon that runs on the central Nagios server and processes passive service check results submitted by clients
nsca.cfg | - Configuration file for the nsca daemon
send_nsca | - Client program that is executed from remote hosts and sends passive service check information to the nsca daemon on the central Nagios server
send_nsca.cfg | - Configuration file for the send_nsca client

Description:

This addon allows you to send passive service check results from remote hosts to a central monitoring host that runs Nagios. The client can be used as a standalone program or can be integrated with remote Nagios servers that run an ocsp command to setup a distributed monitoring environment. Communication between the client and daemon can be encrypted via various algorithms (DES, 3DES, CAST, xTEA, Twofish, LOKI97, RJINDAEL, SERPENT, GOST, SAFER/SAFER+, etc.) if you have the mcrypt libraries installed on your systems.