O/t Network Monitoring

What are you using for network monitoring?
Every once in a while the internet drops and I would like to find out if it something that I'm doing or basically find out if there is a culprit.

I was searching for Network monitors and found this comparison page:
https://en.wikipedia.org/wiki/Comparison_of_network_monitoring_systems
I wonder about Zabbix.

My second choice would be Solar Winds, but I am not sure what product is best.

PRTG is what we use for a lot of things like that. It's free for a small number of sensors. But that will just tell you that it dropped, not why it dropped.