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Features, Installation, and Benefits
Today, Nagios is a reference open-source monitoring tool for traditional IT infrastructures. It allows for the monitoring of hosts, services, and applications, sending alerts, and collecting critical metrics. In this review, we analyze its features, configuration, use cases, and compare it with modern alternatives like Icinga or Zabbix to assess its relevance for developers, system administrators, IT specialists, and professional users.
Problems Solved
What problems does Nagios solve?
Many commercial solutions are expensive or too complex.
Nagios Core, the open-source version, provides extensible monitoring without a license.
It meets the need for basic monitoring with custom alerts, plugins, and multi-system support.
In this context, it also benefits from free software support provided by its community and third-party publishers.
Key Features and Capabilities
Interface
Nagios Core uses a text configuration file without a native graphical interface; the web interface is basic and considered outdated by several users.
Nagios XI offers a modern graphical interface, themes (including a dark mode, Neptune UI), and simplified configuration wizards.
Performance
Modular architecture with plugins, parallel checking, and data collection via PNP4Nagios or OpenSearch depending on the product.
Versions Nagios XI/Log Server/Network Analyzer 2024R2 improve performance, dashboard, and user experience.
Customization
Full support for customizable plugins in various languages (Shell, Python, Perl, etc.).
XI wizards allow quick configuration without writing code: vSphere, OpenAI, Slack, Discord, WinRM, etc.
Security
Support for encryption via SSL/TLS, LDAP/AD authentication, and two-factor authentication by email (Log Server).
Fixes for recent vulnerabilities (privilege escalation, API tokens) in version 2024R2 (March 2025).
Installation and Configuration
How to install and configure?
Download the latest version from the official Nagios Enterprises website.
Install according to the Linux distribution: Debian 12, Ubuntu 24, and other systems are supported by versions 2024R2/2024R2.1.
Configure via
.cfgfiles (Core) or use the wizards (XI) to automate the configuration.Adjust the settings: plugins, alerts, API, users, LDAP/2FA, and themes according to your needs.
Use Cases
Use cases for Nagios
IT department of company X uses Nagios to monitor servers, switches, and critical applications, reducing licensing costs by 30% thanks to Nagios Core.
Support team relies on Nagios Log Server to centralize logs with OpenSearch, benefiting from modern dashboards and two-factor authentication. This integration strengthens its role as a reliable open-source solution for observability.
Complex network architecture: Nagios Network Analyzer integrates with Nmap, Wireshark, and Suricata for event correlation.
Comparison with Alternatives
| Feature | Nagios Core | Nagios XI / Log Server / Fusion | Icinga | Zabbix / Prometheus |
|---|---|---|---|---|
| Open source | ✅ | ❌ (Limited free version) | ✅ | ✅ |
| Graphical Interface | ❌ Very basic | ✅ Modern, assisted | ✅ WATO and improved UI | ✅ Grafana frontend |
| Integrations/plugins | ✅ Via plugins | ✅ Plugins + wizards | ✅ Compatible with Nagios plugins | ✅ Discovery, cloud-native |
| Ease of Use | ❌ Learning curve | ✅ Ideal for beginners + experts | ✅ Simpler | ✅ Automated |
Advantages and Disadvantages
| Advantages | Disadvantages |
|---|---|
| ✅ Completely free (Core) | ❌ Significant learning curve |
| ✅ Highly customizable via plugins | ❌ Core user interface very outdated |
| ✅ Large active open-source community, numerous plugins | ❌ Expensive commercial support for XI/Log Server |
| ✅ Commercial versions bringing UI, API, reports | ❌ Complex scalability and time-consuming maintenance |
Conclusion
Nagios is particularly suitable for:
Technical users looking for a free and highly customizable tool.
Small and medium static environments, on-site infrastructures.
- Teams with scripting and Linux administration skills.
If you are looking for a modern open-source service with an improved interface, automation via service discovery, and scalability for large infrastructures (cloud or containers), consider Icinga, CheckMK, or Zabbix/Prometheus.
