THE WATCHER

You may be familiar with the scene: you hear the sound of your decidedly non-technical partner in the next room shouting “My Internet isn’t working!” Of course, painstakingly checking if the router really is talking to your service provider, and if the DNS server is reachable, would be one possible response. But troubleshooting is a lot easier if you have a software tool that keeps an eye on critical functions and gives you a friendly web-based summary like the one shown in Figure 1. An open source tool called Nagios is perfect for this kind of monitoring. The developers have a long list of plugins at [2]. The plugins can help you monitor websites, databases, networks, and many other things. And if you have a special requirement not covered by the standard plugins, you can tailor a plugin to meet your needs.