How to configure Nagios for audio alerts and mobile notifications

In a Network Operation Centre (NOC) environment, setting up alerts is extremely important. As one of the most popular NOC monitoring systems, Nagios features powerful alerting services. Alerts generated by Nagios can be sent out in various means, so that they can be acted upon immediately. Email notification is the most common option used. This tutorial presents two other ways to send out Nagios alerts: (1) audio alerts via web browser, and (2) audio/vibration alerts via an Android app.