Network monitoring tools/apps

Looking into network monitoring tools, mainly to notify me via email (or sms) if a server goes down (possibly set it up to ping an address every so often and if there’s no response it shoots me a email)
Obviously the more features the better.
Anyone had experience or can recommend me some software?
Answer #1
Nagios is pretty much the de facto for this. Use it along with the many front-ends available for it. You could also use Spiceworks but the monitoring is far inferior to Nagios but it’s easier to set up. If you know a bit of scripting SMS is also pretty easy to set up.
Answer #2
Checking out Nagios now, think this is exactly the type of thing im looking for, i tested Spiceworks a while back wasn’t overly pleased with it.
Thanks for the info!
Any front-ends you can recommend or that you think are essential?
Answer #3
There are a LOT of them around. Centreon is pretty popular.