Nagios Open Source
Depends
Confidence: Medium
Buy if you have sysadmin time and want free, self-hosted monitoring that scales to huge environments.
New check
Comparison
Nagios Open Source and The OpenNMS Group, Inc. both land on Depends.
Buy if you have sysadmin time and want free, self-hosted monitoring that scales to huge environments.
Built for enterprises running large, distributed networks with dedicated ops staff . the free Horizon edition makes it worth piloting at that scale.
| Compare | ||
|---|---|---|
| Verdict | Depends | Depends |
| Best for | Hands-on sysadmin teams | Large distributed networks |
| Who it's not for | Teams without time to edit config files | Small businesses with a handful of devices |
| Privacy | Publicly disclosed and patched vulnerabilities exist; no unpatched crisis in evidence . patch promptly.⁹ | Actively maintained: Meridian undergoes penetration testing, but a past code-execution vulnerability required immediate upgrade. |
| Support quality | No Core support evidence found | Horizon is community-only; paid support via Meridian |
| Public sentiment | Admins rate Core 7.7/10 on TrustRadius across 172 reviews, but Reddit chatter questions how much attention the free version still gets.² | No substantive user review scores surfaced; Reddit and directory coverage centers on release announcements rather than buyer opinions. |
| Biggest gotcha | Core is free, but many features live in paid XI; Reddit users complain the open version lags⁶ | A past vulnerability allowed local and remote code execution and demanded immediate upgrades |