In depth: What's the best way to monitor multiple Linux servers for configuration errors, high load or other problems? The answer is Nagios, which is a fantastic (and free!) networking monitoring system that lets you track multiple servers (HTTP, SMTP, SSH and more) across multiple machines, all backed by a neat user interface.
Nagios gives you an unbeatable overview of all your machines, meaning that you can fix upcoming problems before they turn critical and be certain that you're not missing anything about your network. The basic structure of Nagios is pretty simple: you set up one machine as your Nagios server, and it gathers information on the client machines you point it at, then displays it in a neat web page format. Read on to learn how to get started with Nagios on your own network!