Monitoring computer and/or network downtime?

Question by Mark F: Monitoring computer and/or network downtime?
I have been asked by my MD to track downtime of our IT and communications infrastructure. Is there a easy to use program or web application that can be used for this?

Many Thanks

Best answer:

Answer by Phlll
Nagios should work. It’s a hassle to set up, though.

What do you think? Answer below!