I suggest Icinga for monitoring Systems & Network.
“Icinga is a fork of Nagios and is backward compatible. So, Nagios configurations, plugins and addons can all be used with Icinga. Though Icinga retains all the existing features of its predecessor, it builds on them to add many long awaited patches and features requested by the user community.”
Thanks for the suggestion! We met with Dotcom-Monitor at HostingCon this year and they’re interested in working with us to do some integration – what does everyone think? Would you be interested in something like that?