Xplico is a Network Forensic Analysis Tool (NFAT)
An open source search engine with RESTFul API and crawlers
PHP-based looking glass for Cisco, Juniper & Zebra/Quagga routers
Yet another monitoring system
OPTOSS Next Gen Network Management System (NG-NetMS)
REST interface and configuration GUI for Nagios
Heuristic System Control
Webinterface to (un)ban IPs in Fail2Ban
PotHead
A client for the MikroTik RouterOS API protocol, written in PHP.
Open Source SIEM
Open source tool to monitor your servers and websites
Netflow visualisation and investigation tool
DOCSIS network management
Energy and environmental monitoring of the server room
Server & Service Management and Monitoring
The Simplest Multi-User Latency Monitoring Web App
Scalable, distributed monitoring system for high-performance computing