Nagios Core is a powerful open source monitoring engine with support for plugins, add-ons, NCPA, Mod-Gearman, and community-driven integrations.

Nagios, the industry-standard in IT infrastructure monitoring, provides insights into system performance and availability. Learn about Nagios' history, mission, and core principles.

Configure Nagios to monitor critical IT infrastructure components, including system metrics, network protocols, applications, services, servers, and network infrastructure.

Nagios excels at network monitoring with proven reliability detecting and distinguishing between hosts that are down versus unreachable.

Download Nagios Core, XI, plugins and agents for free. Monitor Windows, Linux, & network infrastructure with the world's most trusted monitoring solution.

Ready to Start Monitoring? Join thousands of organizations who trust Nagios for their infrastructure monitoring.

Trusted by 1M+ users worldwide, Nagios Core provides complete monitoring of your entire IT infrastructure environment – including websites, DNS, servers, routers, switches, services, …

Whether you want to monitor networking devices, log data, flow data, or virtually anything that is connected to a network, Nagios has you covered with a suite of powerful solutions to meet …

Nagios offers the most complete Open Source powered monitoring solution in the IT management space. Thousands of Nagios extensions and add-ons, along with a high degree of …

In addition to including individual Open Source Software components, the Nagios CSP distribution includes a pre-made virtual machine of a free edition of Nagios XI – our flagship monitoring …