monitoring system for systems, networks and applications

 Xymon (previously called Hobbit) is a network- and applications-
 monitoring system designed for use in large-scale networks. But it will
 also work just fine on a small network with just a few nodes. It is
 low-overhead and high-performance, with an easy to use web front-end.
 It handles monitoring of network services, and through client packages
 it can also be used to monitor server- specific items. Alerts can
 trigger when monitoring detects a problem, resulting in e-mails or
 calls to your pager or mobile phone.
 .
 Xymon has a great deal of inspiration from the non-free Big Brother
 package, but does not include any Big Brother code.