NetFlow Monitoring
Advantages of a NetFlow Monitor
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.
Configuring The NetFlow Monitor
Configure the NetFlow protocol on the router to send NetFlow packets to the computer running PRTG Network Monitor:
- Configure a NetFlow Sensor in PRTG (NetFlow Sensors are included in all PRTG licenses, even in the Freeware)
- 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.
Test NetFlow Monitoring
You can test our NetFlow monitor with the 30-Day-Trial-Edition of PRTG Network Monitor, which supports unlimited sensors. The Commercial Editions are required if you want to monitor more than 10 sensors after the 30 day trial period. All PRTG licenses, including the freeware, allow you to use NetFlow. The number of NetFlow sensors is only limited by number of sensors included in your license. Licenses for Paessler's NetFlow monitor PRTG start at $400 / €300.
