Working with Sensors
Since each network device (or "server") usually has several
parameters or services that should be monitored you can set up various sensors
to monitor each and every aspect of a server (e.g. CPU load, webserver
responsiveness, SMTP responsiveness, PING time, etc.) So a "server" has several
"sensors" by which you will monitor all aspects of the server.
Each sensor is shown with a color depicting its current
state, e.g. DOWN, UP, PAUSED, or OK.

See Managing Sensors for more
information on adding and editing sensors.