NetFlow Monitoring

Adding to normal bandwidth monitoring capabilities based on SNMP, a NetFlow monitor allows administrators to discern actual bandwidth usage based on multiple parameters, such as IP addresses, port numbers, protocols, etc., using NetFlow Sensors.

Cisco devices with NetFlow Support track the bandwidth usage of the network internally. NetFlow monitoring based on Cisco's NetFlow protocol is supported by most Cisco routers and certain Cisco switches. These devices can be configured to send pre-aggregated data to the computer running a NetFlow monitor such as PRTG Network Monitor which can then analyze the data. This way, PRTG's computing load is much lower. This option is recommended for high traffic networks.

As such, NetFlow monitoring can give you information similiar to a packet sniffer on where, why, how and by whom specific applications are being used and how the usage might affect the network.

Configure the NetFlow protocol on the router to send NetFlow packets to the computer running PRTG Network Monitor:

• Configure a NetFlow Sensor in PRTG (2 NetFlow Sensors are included in each commercial license and in the 30-day-trial license)
• Create one new NetFlow Sensor for each IP or protocol to be monitored, and apply a filter based on the IP or protocol for each item you want to monitor
• Or: If you do not need long term accounting data for each PC and only want to know the current and recent traffic by IP or protocol, you can  create just one NetFlow Sensor and enable the Toplist feature based on IP or protocol.

Further information on setting up NetFlow Sensors for NetFlow monitoring can be found in the online manual and in the online knowledge base article.

You can test our NetFlow monitor with the 30-Day-Trial-Edition of PRTG Network Monitor, which supports 5,000 sensors and 2 NetFlow Sensors. The Commercial Editions are required if you want to continue NetFlow monitoring after the 30 day trial period. NetFlow Sensors can be purchased additionally, if you require more than the 2 included sensors. Licenses for Paessler's NetFlow monitor PRTG start at $380 / €250. (Please note that the Freeware Edition does not support NetFlow monitoring.)