Using NRDP

Passive checks are sent to Nagios via the external command pipe, which can only be accessed on the same machine where Nagios is running. Very often passive checks are carried out on one or more remote hosts. This requires a mechanism to pass results from the machines that perform the tests to the computers running the Nagios daemon, which will process the results.

NRDP is a technology that allows sending results to a Nagios instance remotely. It provides a simple API to send the results to a Nagios instance using the HTTP protocol and leveraging existing web servers such as Apache web server that we have installed in Chapter 2, Installing Nagios 4.

NRDP consists of two parts-server and client. The part responsible for receiving check results from remote hosts and passing them to Nagios is the server. Once installed and added into the Apache configuration, it will accept requests, validate the token used to authenticate the request and pass the information to Nagios. The client part...