One of the key features of Nagios is its extensibility. There are multiple ways in which Nagios can be tailored to suit your needs. It is also possible to integrate Nagios tightly with your applications and benefit from a powerful mechanism for scheduling and performing checks.

The first and the easiest way to adapt Nagios is to perform checks customized to your company's needs. The default Nagios plugins suit most needs very well — they allow simple checking of databases, web sites, and various networked or local services. However, in many cases this may not be enough. You might want to create a script to verify that critical tables in a database are not corrupted, or that your website actually works and communicates with web services over SOAP.

Another area that can be customized in a variety of ways is how users are notified about problems. By default, Nagios is able to send emails to users when a problem occurs. There are also plugins for various protocols...