LibreNMS

Observium

Observium is a network monitoring platform that automatically discovers devices and services on a network and collects real-time and historical performance data, presenting it through a web-based dashboard. It supports over 450 device operating systems and vendors, including Cisco, Juniper, HP, Dell, Windows, and Linux, and provides threshold, state, and syslog-based alerting. Beyond monitoring, Observium includes traffic accounting and billing features, rule-based automatic device grouping, network mapping, and a RESTful API for integrating with other tools. It ships in a free Community edition, alongside paid Professional and Enterprise editions that add real-time SVN updates and support hours, and is used by organizations including Twitch, eBay, and Spotify.

Checkmk

Checkmk is an IT observability platform that monitors servers, network devices, applications, containers, and storage from a single system, aimed at enterprises and managed service providers running hybrid and cloud infrastructure. It ships with over 2,000 pre-built integrations and automated discovery so new hosts and services can be added to monitoring with minimal manual configuration. The platform includes dependency mapping, SLA reporting, availability tracking, and AI-assisted root cause analysis to speed up troubleshooting. It is offered as a free open-source Community edition alongside commercial Pro, Ultimate, and fully managed Cloud editions, letting teams scale from small deployments to large, multi-site monitoring environments without switching tools.

OpenNMS Horizon

OpenNMS Horizon is an open-source network management platform that provides fault, performance, and availability monitoring for large, heterogeneous networks. It offers a flexible, modular architecture that can be customized to fit the needs of service providers, enterprises, and research institutions. The platform includes a powerful event engine, customizable dashboards, and extensive reporting capabilities, all backed by a robust API for integration with third‑party tools. Horizon is community‑driven and can be deployed on‑premises or in private clouds, giving organizations full control over their monitoring data.

Skydive

Skydive is a network topology and protocol analyzer that provides a real-time, global view of your entire network infrastructure. It actively probes devices and captures traffic to build a dynamic, interactive map of all your network elements, including hosts, switches, routers, and virtual machines. This makes it an invaluable tool for network engineers and DevOps teams who need to troubleshoot issues, monitor performance, and understand complex network dependencies. The platform excels at automating network discovery, eliminating the need for manual inventory tracking. It uses a combination of active probing and passive traffic capture to continuously update its topology map, ensuring that you always have an accurate picture of your network's current state. With Skydive, you can drill down into specific nodes to view real-time metrics, inspect flows, and even replay captured packets for deep analysis. Skydive is particularly well-suited for dynamic environments like Kubernetes clusters and cloud-based infrastructures, where network topologies change frequently. Whether you're a network administrator looking to pinpoint a connectivity problem, a security analyst investigating suspicious traffic, or a developer trying to understand how your microservices communicate, Skydive offers the visibility you need. It is an open-source project that can be self-hosted, providing flexibility and control over your network monitoring data.

Zabbix

Zabbix is a powerful open‑source monitoring platform that provides real‑time visibility into the performance and availability of IT infrastructure, applications, and services. It combines a flexible data collection engine with a rich web‑based UI for dashboards, reporting, and alerting. Designed for large‑scale environments, Zabbix supports agent‑based and agentless monitoring, customizable templates, and extensive integration options, making it suitable for enterprises, service providers, and complex hybrid clouds.