The Merlin project was initially started to create an easy way to set up distributed Nagios installations, allowing Nagios processes to exchange information directly as an alternative to the standard method using NSCA. It has also been extended with fault tolerance, the ability to store status information in a database, and other features. This allows Merlin to function as a backend for applications such as the Ninja project.
OpMon is a network and system monitoring application based on Nagios with extended support for capacity planning, SLA, SLM, network discovery, service catalogs, report schedule, Davinci, a dashboard builder, and much more. OpMon provides a GUI for Nagios as well as full multi-language support. The license to use the opmon proprietary modules is free for 2 hosts and 20 services. OpMon comes with many open source applications like phplogcon, Nedi, ntop, nagtrap, OCSInventory, OTRS, and opcfg.
Opsview Core is a network monitoring software application. It solves the challenges of monitoring modern IT and network systems. It is a drop-in replacement for Nagios Core, with full support for its plugins and 100% compatibility. It is easy to install and configure and is ideal for monitoring applications networks, and Windows, Linux, and Unix servers. VMWare, KVM, Xen, and Microsoft Hyper-V are supported, and Amazon EC2 and other cloud services can be monitored. It works with Opsview Mobile to allow you to monitor your systems on the go.
Panoptes is a scalable, extensible network and host monitoring tool. It includes a dynamic Web management interface based on the Dojo toolkit. It monitors SNMP, TCP port availability, ICMP, HTTP response and content, and SSL certificates internally. It supports monitoring anything else via shell scripts. It also includes a packet capture tool for discovery of hosts, port, and OS.