Q: I need a (hopefully)free way to monitor a web farm and know if one of the servers goes offline.
A: IPCheck Server Monitor allows you to monitor your server(s) and be notified via email when they are down. The free version can be used with up to 3 sensors, which can be simple HTTP, PING or PORT requests. The interface is browser based and provides a detailed overview with statistics on each of the monitored devices. IPCheck Server Monitor offers additional features and monitoring options, however all of thenm are disabled in the freeware version and can only be evaluated upon request. The free version is good for basic monitoring of a personal server.