Book Image

Nagios Core Administration Cookbook - Second Edition

By : Tom Ryder
Book Image

Nagios Core Administration Cookbook - Second Edition

By: Tom Ryder

Overview of this book

Nagios Core is an open source monitoring framework suitable for any network that ensures both internal and customer-facing services are running correctly and manages notification and reporting behavior to diagnose and fix outages promptly. It allows very fine configuration of exactly when, where, what, and how to check network services to meet both the uptime goals of your network and systems team and the needs of your users. This book shows system and network administrators how to use Nagios Core to its fullest as a monitoring framework for checks on any kind of network services, from the smallest home network to much larger production multi-site services. You will discover that Nagios Core is capable of doing much more than pinging a host or to see whether websites respond. The recipes in this book will demonstrate how to leverage Nagios Core's advanced configuration, scripting hooks, reports, data retrieval, and extensibility to integrate it with your existing systems, and to make it the rock-solid center of your network monitoring world.
Table of Contents (18 chapters)
Nagios Core Administration Cookbook Second Edition
About the Author
About the Reviewer

Checking an alternative SSH port

In this recipe, we'll learn how to deal with the common situation of a machine running an SSH daemon that is running on an alternative port; in this case, a service definition that uses check_ssh as used in the recipe Monitoring SSH for any host fails, because the plugin defaults to using the standard SSH TCP port number 22.

This kind of setup is common in situations where an SSH server should not be open to the general public and is often employed as a "security by obscurity" method to reduce automated attacks against the server. The SSH daemon is, therefore, configured to listen on a different port, usually with a much higher number, and the administrators who need to use it are told what the port number is.

We'll deal with this situation and monitor the service in Nagios Core, even though it's running on a non-standard port. We'll do this by defining a new command that checks SSH on a specified port number and creating a service definition that uses that...