Nagios was created by Ethan Galstad in 1999 as a network monitoring solution. The project began as a hobby and grew into one of the most influential open-source monitoring platforms, spawning an entire ecosystem of forks and derivatives. The name “Nagios” is a recursive acronym: “Nagios Ain’t Gonna Insist On Sainthood” (with “Nagios” replacing the first “Nagios”).
Ethan Galstad, a software developer from North Dakota, began developing what would become Nagios in 1999. The project was initially called NetSaint and was designed to:
- Monitor network services (SMTP, HTTP, SSH, etc.)
- Check host resources (disk space, CPU load, etc.)
- Alert administrators when problems occurred
- Provide a web interface for status viewing
The initial design was influenced by:
- Big Brother: Early commercial monitoring tool
- Starter: Another open-source monitoring project
- Custom scripts Ethan had written for his own use
NetSaint 1.0 was released in 2002 under the GPL license. The initial release featured:
- Plugin-based architecture
- Service and host monitoring
- Contact notifications
- Web-based status interface
- Event handling capabilities
Due to trademark concerns with the name “NetSaint,” Ethan Galstad renamed the project to Nagios in 2002. The recursive acronym was created to maintain the “NS” initials while giving the project a unique identity.
| Year |
Version |
Milestone |
| 1999 |
- |
Development begins as NetSaint |
| 2002 |
1.0 |
First public release as NetSaint |
| 2002 |
1.0 |
Renamed to Nagios |
| 2003 |
1.2 |
Improved plugin system |
| 2004 |
2.0 |
Enhanced scalability, passive checks |
| 2005 |
2.5 |
Improved web interface |
| 2006 |
3.0 |
Major architecture rewrite |
| 2007 |
3.0.4 |
Stability improvements |
| 2008 |
3.1 |
Performance improvements |
| 2009 |
3.2 |
Enhanced event handling |
| 2010 |
3.3 |
Final 3.x release |
| 2011 |
3.4 |
Bug fixes and improvements |
| 2012 |
3.5 |
Last major 3.x update |
| 2013 |
4.0 |
Major release with improvements |
| 2014 |
4.1 |
Enhanced performance |
| 2015 |
4.2 |
Security improvements |
| 2016 |
4.3 |
Modernization updates |
| 2017 |
4.4 |
Bug fixes and stability |
| 2018 |
4.4.5 |
Security patches |
| 2019 |
4.4.6 |
Maintenance release |
| 2020 |
4.4.7 |
Continued maintenance |
| 2023 |
4.5.4 |
4.5.x series begins |
| 2024 |
4.5.10 |
Ongoing development |
| 2025 |
4.5.11 |
Current stable release (January 2025) |
The 1.x series established core architecture:
- Plugin-Based: External scripts for checks
- Polling Model: Active checks at intervals
- Flat Configuration: Text-based config files
- CGI Frontend: Web interface via CGI scripts
- Notification System: Email alerts
Version 2.0 introduced:
- Passive Checks: Accept external check results
- Distributed Monitoring: Multiple Nagios instances
- Improved Scalability: Better performance
- Enhanced Notifications: More notification options
- Event Handlers: Automated response to events
Version 3.0 was a major rewrite:
- New Core Engine: Improved performance
- Object-Oriented Design: Better code organization
- Enhanced Caching: Faster status updates
- Improved Web Interface: Better usability
- Better Logging: Enhanced audit trails
Version 4.0 brought modernization:
- Performance Improvements: Faster check execution
- Security Enhancements: Better authentication
- Modern Web Interface: Improved UX
- API Support: REST-like interfaces
- Better Integration: Third-party tools
In 2008, Ethan Galstad founded Nagios Enterprises to:
- Provide commercial support
- Develop enterprise products
- Offer training and certification
- Build partner ecosystem
- Nagios XI (2009): Commercial distribution with enhanced UI
- Nagios Log Server (2014): Log management solution
- Nagios Network Analyzer (2013): Network traffic analysis
- Nagios Fusion (2016): Multi-source monitoring
- 2008: Founded in Minneapolis, Minnesota
- 2010: Nagios XI launched
- 2015: 50+ employees
- 2020: Global presence
- 2026: Continued operations
Nagios’s architecture inspired several forks:
- Created by former Nagios developers
- Added features missing from Nagios
- Modern web interface
- Better configuration management
- Forked from Nagios 4.x
- Performance improvements
- Modern features
- Active development
- Python rewrite of Nagios
- Distributed architecture
- Modern design
- Later evolved into Arbiter
Nagios’s plugin architecture enabled massive community contributions:
- Official Plugins: 100+ maintained plugins
- Exchange Plugins: 5,000+ on Nagios Exchange
- NRPE: Remote check execution
- NSCA: Passive check submission
- Custom Plugins: Community-contributed scripts
Nagios became the de facto standard for open-source monitoring:
- Installations: Millions worldwide
- Enterprise Use: Fortune 500 companies
- Service Providers: Managed service providers
- Government: Public sector deployments
- Nagios Certified Professional: Official certification
- Training Courses: Official and third-party
- Books: Multiple published guides
- Online Resources: Extensive documentation
- GitHub Stars: 2,000+
- Downloads: Millions of installations
- Community: Active user base
- Company: Nagios Enterprises continues operations
- Ecosystem: Forks and derivatives thriving
- Maintenance releases for Nagios Core
- Active development of Nagios XI
- Security patches
- Community plugin updates
- Modernization: Continued UI improvements
- Cloud Integration: Better cloud monitoring
- API Enhancement: Improved automation
- Security: Enhanced access controls
- Community: Supporting the ecosystem
Any questions?
Feel free to contact us. Find all contact information on our contact page.