Remstats is a system of perl-scripts using Tobi Oetiker's RRDtool to perform network and server monitoring. RRDtool supplies the database and graphing functions, and remstats supplies the data-collection and Web-page generation.
Remstats was designed to collect data from various sources, including, but not limited to, SNMP. The tool produces Web pages with multiple graphs per page, as I wanted to be able to correlate information between graphs. It also produces configurable alerts based on any data that is being collected.