nagios

Powerful network monitoring system

Nagios is a host and service monitor designed to inform you of network problems before your clients, end-users or managers do. The monitoring daemon runs intermittent checks on hosts and services you specify using external "plugins" which return status information to Nagios. When problems are encountered, the daemon can send notifications out to administrative contacts in a variety of different ways (email, instant message, SMS, etc.). Current status information, historical logs, and reports can all be accessed via a web browser.