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
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Using an alternative check command for hosts


In this recipe, we'll learn how to deal with a slightly tricky case in network monitoring: that of monitoring a server that doesn't respond to PING but still provides some network service that requires checking.

It's good practice to allow PING where you can, as it's one of the stipulations in RFC 1122 and a very useful diagnostic tool not just for monitoring but for troubleshooting. However, sometimes, servers that are accessed only by a select few people might be configured not to respond to these messages, perhaps for reasons of secrecy. It's quite common for domestic routers to be configured this way.

Another very common reason for this problem, and the example we'll address here, is checking servers that are behind an IPv4 NAT firewall. It's not possible to address the host directly via an RFC1918 address such as 192.168.1.20 from the public Internet, and pinging the public interface of the router doesn't tell us whether the host for which...