# About Nagios

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See Also: Quickstart Installation Guides

What Is This?

Nagios® is a system and network monitoring application. It watches hosts and services that you specify, alerting you when things go bad and when they get better.

Nagios was originally designed to run under Linux, although it should work under most other unices as well.

Some of the many features of Nagios include:

- Monitoring of network services (SMTP, POP3, HTTP, NNTP, PING, etc.)
- Monitoring of host resources (processor load, disk usage, etc.)
- Simple plugin design that allows users to easily develop their own service checks
- Parallelized service checks
- Ability to define network host hierarchy using "parent" hosts, allowing detection of and distinction between hosts that are down and those that are unreachable
- Contact notifications when service or host problems occur and get resolved (via email, pager, or user-defined method)
- Ability to define event handlers to be run during service or host events for proactive problem resolution
- Automatic log file rotation
- Support for implementing redundant monitoring hosts
- Optional web interface for viewing current network status, notification and problem history, log file, etc.

System Requirements

The only requirement of running Nagios is a machine running Linux (or UNIX variant) and a C compiler. You will probably also want to have TCP/IP configured, as most service checks will be performed over the network.

You are not required to use the CGIs included with Nagios. However, if you do decide to use them, you will need to have the following software installed...

1. A web server (preferrably Apache)
2. Thomas Boutell's gd library version 1.6.3 or higher (required by the statusmap and trends CGIs)

Licensing

Nagios is licensed under the terms of the GNU General Public License Version 2 as published by the Free Software Foundation. This gives you legal permission to copy, distribute and/or modify Nagios under certain conditions. Read the 'LICENSE' file in the Nagios distribution or read the online version of the license for more details.

Nagios is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE WARRANTY OF DESIGN, MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgements

Several people have contributed to Nagios by either reporting bugs, suggesting improvements, writing plugins, etc. A list of some of the many contributors to the development of Nagios can be found at http://www.nagios.org.

Downloading The Latest Version

You can check for new versions of Nagios at http://www.nagios.org.

Nagios and the Nagios logo are trademarks of Ethan Galstad. All other trademarks, servicemarks, registered trademarks, and registered servicemarks may be the property of their respective owner(s).