NightCrawler is an application that can monitor web servers. The application offers a variety of options, including the interval at which it polls your selected servers. Each server will have one of three background colors. The white background is for servers not currently being monitored, red is for those that could not be reached or returned an error status code, and green is for those servers responding successfully. A mouse rollover of any server name will tell you the latest time the server was monitored and the result code. Menu items include options for setting which servers are to be monitored, setting the monitor interval, starting and stopping the monitoring service. Additionally, each server has a checkbox next to it to immediately deactivate monitoring for that server.

A screen shot of NightCrawler's polling interval options.

A screen shot of NightCrawler in action.