Paessler Netflow Tester - Network Flow Traffic Analysis

Key Features

• Our NetFlow Testers are small programs that simply dump the data of all NetFlow packets that a computer receives from a Cisco router.
• This can be useful when debugging bandwidth monitoring configurations based on Cisco\\'s NetFlow protocol (both v5 and v9).
• First the NetFlow protocol must be enabled and configured on the router.
• The router must be given the IP address of the computer running NetFlow tester so that the UDP data packets with NetFlow data are sent to this computer.
• Just follow these simple instructions: 1) Download Paessler Netflow Tester.
• Netflow5Tester.exe for testing NetFlow version 5 and Netflow9Tester.exe for testing NetFlow version 9.
• 2) Enter the IP and port number that you have configured as NetFlow packet target in your Cisco Router.
• Usually selecting \"Any IP\" should work, in some cases the IP must be explicitly selected.
• 4) You should now see a line in the logfile for each packet the computer receives.
• Each line shows the time, NetFlow version, number of flows and the IP of a packet (Note: You need NetFlow v5 for PRTG Traffic Grapher; PRTG Network Monitor supports both NetFlow v5 and v9).
• NetFlow5Tester only: Enable \"Show Flow Data instead of packet data\" to also show the corresponding flow data.
• If you do not see any activity then the system does not receive any NetFlow data (e.g.
• due to misconfiguration of the router or a firewall blocking the packets, etc.) .

Technical Specifications

• **Publisher:** Paessler.com
• **License:** Freeware
• **Operating System:** Windows 7, Windows 8, Windows 10, Windows 11
• **Last Updated:** October 15, 2025
• **Category:** Internet / Network Tools