Xymon monitors your hosts, your network services, and anything else you
configure it to do via extensions. Xymon will periodically generate
requests to network services - HTTP, FTP, SMTP and so on - and record if
the service is responding as expected. Through the use of agents
installed on the servers (the xymon-client package), you can also
monitor local disk utilization, log files and processes.

Xymon is the successor to the BBGEN toolkit, which has been available as
an add-on to Big Brother since late 2002. It was also previously known
as Hobbit. If you have used BBGEN before, Xymon will seem quite
familiar.

You should install this package if you want this machine to monitor
services running on other machines.