The description of Paessler NetFlow Generator - Play With New Friends
Netflow Generator creates artificial NetFlow Version 5 data streams without the need for NetFlow compatible hardware. It is the perfect tool for testing the NetFlow functionality of PRTG or other NetFlow compatible programs. NetFlow Generator runs on a PC and sends NetFlow 5 Packets (via UDP) to a specific target computer which processes the data. You can create various patterns and loads of traffic. While the simulator is active it will create NetFlow packets which contain information about the selected traffic pattern. These packets contain the same information as a router/switch would send if it saw the simulated traffic pattern (the simulated traffic itself is not generated).