FreeNATS (the Free Network Automatic Testing System) is an open-source network monitoring software application developed by David Cutting under the banner of PurplePixie Systems. FreeNATS is free software licensed under the terms of the GNU General Public License version 3 as published by the Free Software Foundation. Overview Monitoring of network services (SMTP, POP3, HTTP, ICMP (ping) Limited monitoring of host resources (processor load, disk usage) on a majority of network operating systems, including Microsoft Windows and Linux through agent-based testing Plugin design that allows users to easily develop their own service checks depending on needs, by using PHP (or other languages or scripts wrapped in PHP) Some ability to define network host hierarchy using "master" nodes allowing link failures to suspend monitoring Event-based system allowing failure notifications to be sent in customised email (suitable for email-to-SMS) or to utilise third-party notification scripts via a plug-in Ability to define event handlers to be run during service or host events for proactive problem resolution Automatic data retention cleanups Full web-interface for management and monitoring Ability to "publish" views and graphs within third-party web pages See also Comparison of network monitoring systems References External links purplepixie.org/freenats, official website FreeNATS Wiki Support Forum for FreeNATS NetworkWorld.com Article on FreeNATS PC Quest Article on FreeNATS Internet Protocol based network software Free network management software