The ServerMonitor tool 

These docs describe the new version of ServerMonitor, which is an adaptation of a tool that was provided as part of the Frontier package offered by UserLand, before the open source release.

It does basically the same thing, but with less fuss and muss.

Overview 

It runs every minute, checking each of the servers you've configured it to ping, to see if they're still running. It gathers stats from the servers.

The report is available from a dynamic page or a static one.

The OPML Editor ships with a responder for ServerMonitor, but it is disabled by default. If you set user.opmlEditor.prefs.flRespondToServerMonitor to true, on the client machine, it will respond to ServerMonitor pings. The responder is at user.betty.rpcHandlers.pingServerMonitor.