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 a powerful open-source monitoring tool that excels in customization and flexibility, making it suitable for complex IT environments. In contrast, PRTG Network Monitor offers a user-friendly interface and comprehensive monitoring features, making it a better choice for organizations looking for ease of use and quick deployment.