pmacct is a small set of multi-purpose passive network monitoring tool
Web-based Traffic and Security Network Traffic Monitoring
FlowViewer is a web-based netflow data analysis tool.
free netflow analyzer
Enterprise Network Flow Collector (IPFIX, sFlow, Netflow)
Analizes PCAP files and gives statistics about IP packets.
Various TCP/IP servers, clients and network management tools
A Networking Monitoring Tool Based on the Google Maps API
Dashboard of network top-talkers using netflow sources
CactiFans is a self installing based off CentOS customized Cacti