Nagios known as Nagios Core, is a free and open source computer-software application that monitors systems, networks and infrastructure. Developed by Nagios Enterprises
License: Open Source
Nagios is an open-source monitoring tool that excels in customizability and community support, making it suitable for large-scale environments, while Pandora FMS offers a more user-friendly interface and comprehensive monitoring capabilities, making it ideal for organizations looking for an all-in-one solution.