Nagwin!

An uncompromising mature enterprise-level platform designed for real-time monitoring of millions of metrics collected from tens of thousands of servers, virtual machines and network devices, effortlessly scaling to even larger environments.

Icinga is a fork of Nagios and is backward compatible. So, Nagios configurations, plugins and addons can all be used with Icinga. Though Icinga retains all the existing features of its predecessor, it builds on them to add many long awaited patches and features requested by the user community. Icinga is an enterprise grade open source monitoring system which keeps watch over a network and any conceivable network resource, notifies the user of errors and recoveries, and generates performance data for reporting. Scalable and extensible, Icinga can monitor complex, large environments across dispersed locations. Icinga is licensed under GPL V2. »

OpenNMS is an enterprise grade network monitoring and network management platform developed under the free software or open source model. It consists of a community-supported, free-software project as well as an organization offering commercial services, training and support.

Shinken is an open source computer system and network monitoring software application compatible with Nagios. It's written in Python and therefore is able to run on all platforms where a Python interpreter is available.In contrast to Nagios it is not a monolithic system. Shinken runs as a bunch of highly specialized processes, avoiding the bottlenecks of a single-process design. This parallelity allows to run Shinken not only on one single server. It's components can be distributed over a whole server farm, which results in incredible scalability.Shinken is actively developed and already got more features than Nagios (like priorities for objects, business processes, auto-generation of services, discovery,...) »

Opsview Atom is ideal for personal use, SoHo setups, test or lab environments or just to get your hands dirty with all of Opsview's monitoring functionality!

Opsview is award winning unified service monitoring software for complex, distributed IT infrastructures.

Zenoss (Zenoss Core) is an open source application, server and network management platform based on the Zope application server. Released under the GNU General Public License (GPL) version 2, Zenoss Core provides a web interface that allows system administrators to monitor availability, inventory/configuration, performance and events.

IT monitoring has never been easier - lean back and let CloudRadar keep an eye on your servers, services and hosts. Up and running in minutes. No back doors.

System Center Operations Manager 2012 R2 uniquely enables customers to reduce the cost of data center management across server operating systems and hypervisors through a single, familiar and easy to use interface. Through numerous views that show state, health and performance information as well as alerts generated according to some availability, performance, configuration or security situation being identified, operators can gain rapid insight into the state of the IT environment, and the IT services running across different systems and workloads. »

Sentinet3 is an enterprise class unified proactive monitoring device able to monitor Systems, Applications, and Networks.

Our open and flexible server and network monitoring solution delivers a unified view of your entire IT environment. Monitor up to 100,000 devices from a single server, with distributed and redundant solutions for nearly infinite scalability.

Effortless monitoring for your online service

IPSentry provides monitoring of all aspects of your network 24/7 and alerts you when there is a potential problem.