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The Industry Standard in Open Source IT Monitoring Tools.

Free, powerful monitoring and alerting for servers, networks, applications and services.

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Nagios XI | Extended Insights

The complete IT infrastructure monitoring tool

Powered by Nagios Core monitoring engine
Pre-installed plugins and agents
Easy to use monitoring wizards
Powerful dashboards and reports
Learn More About Nagios XI

Why Choose Nagios for IT Monitoring?

Complete Infrastructure Monitoring

Monitor Windows & Linux machines, networks, and services to prevent downtime before it impacts critical business processes.

Powerful Plugin Architecture

Extend capabilities with thousands of plugins and add-ons including NCPA, NRPE, NSCA, and other custom monitoring solutions.

Enterprise-grade Open Source

Free, open-source monitoring platform trusted in enterprise environments and backed by 25+ years of monitoring expertise.

Already using Nagios Core? Switch to Nagios XI — get the enterprise dashboards, easier configuration, and scalability your team needs, without starting from scratch.

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Popular Open Source Projects

Production-ready monitoring trusted by thousands of organizations worldwide.

Nagios Core

The monitoring engine that started it all. Monitor websites, servers, switches, routers, firewalls, ports, applications, metrics, and more.

NCPA (Nagios Cross-Platform Agent)

Monitor Windows, Linux, and Mac in real time. NCPA is a cross-platform agent for servers, system metrics, applications, and networks.

Nagios Plugins

50+ ready-made checks packaged with Nagios including check_ping, check_ssh, check_cpu, check_memory, check_linux, and more.

Nagios Mod-Gearman

Adds scalability and performance to Nagios Core, enabling users of Nagios Core and XI to effectively monitor large environments.

Nagios Configuration Tools

Web UIs, auto-discovery scripts & change management interfaces to simplify Nagios configuration without manual file editing.

Nagios Visualization Add-ons

Transform Nagios data into dashboards, network maps & performance graphs for intuitive monitoring and business insights.

Nagios Core Services Platform

Want everything in one comprehensive package? Get all essential Nagios open-source projects plus a pre-configured Nagios XI VM in one unified download.

Nagios Core monitoring engine
50+ Official Nagios Plugins
Nagios Cross-Platform Agent
Configuration and Visualization Tools
Pre-Configured Virtual Machine
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The Power of Community

Join thousands of users, developers, and contributors who make Nagios the world’s most trusted monitoring solution.

Global Community

Nagios Core is supported by a global community of users, developers, and contributors. They extend its capabilities every day, helping monitor everything from simple setups to complex infrastructure.

Built to Be Shared

Nagios was designed from the start to be open and flexible. That community-driven foundation is what makes it powerful–and why it’s been trusted for over two decades.

Nagios Exchange

Nagios Exchange is home to thousands of community-built plugins, scripts, and add-ons. From servers and networks to applications and services, it makes extending Core easy and accessible.

Resources

Nagios Exchange

Browse thousands of community plugins.

Community Forums

Get help from other Nagios users.

Nagios Library

Search guides, docs, and resourcs.

Training & Certification

Professional training and certification programs.

Plugin Development Guidelines

References for plugin developers.

Nagios Manuals

Online manuals for Nagios projects.

Popular Articles

Comparison

6 min read

Nagios Core vs Nagios XI

A comparison of features, capabilities, and use cases to help you choose between Nagios Core and Nagios XI for your monitoring needs.
Upgrade

5 min read

Roadmap: Nagios Core to Nagios XI

Step-by-step guide for upgrading from Nagios Core to Nagios XI, including planning considerations and migration best practices.
Webinar

20 min read

Benefits of Migrating to Nagios XI from Core

Watch this webinar to discover the key advantages of upgrading from Nagios Core to XI, including enhanced features and improved usability.

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Ready to Start Monitoring?

Join thousands of organizations who trust Nagios for their infrastructure monitoring.

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Learn About Nagios XI