Been taking a look at http://www.nagios.org/ installed on my local lan
with nagios running on Mandrake 9.1 anyone had a try at using this app
"netsaint"
Yes, I use it to monitor my live servers. It can send you an email (or SMS
using an email-to-SMS gateway) if a server becomes inaccessible, it can
monitor individual services (https, smtp etc), you can set different alerts
for different hours/days, it can tell the difference between a host/service
going down and a network problem en-route to that host. Of course my
servers run GNU/Linux so it has never had to alert me because nothing ever
goes down (except for maintenance) :-) Nagios is a bit complex and tedious
to set up but works well.