14.04.2019

FastNetMon configuration for Netflow and IPFIX

FastNetMon supports many different implementations of standard Netflow protocol:

  • Netflow v5
  • Netflow v9
  • IPFIX

Also, it support many vendor specific implementations (list isn’t complete):

  • Netstream
  • jFlow
  • cFlow

You can enable Netflow plugin this way:

Specify port for Netflow capture (2055 is default port)

Then specify interface for listening (0.0.0.0 is default):

Urgent remark about Netflow sampling. FastNetMon could automatically extract sampling rate from Netflow v5, v9 and IPFIX but in some rare cases you should specify it explicitly

Also, you should carefully review your active and inactive timeouts from Netflow agent side and set them to smallest possible values which do not overload your hardware. Then you need to select maximum value from them and use it for average_calculation_time option in seconds. Without these changes FastNetMon could calculate traffic bandwidth incorrectly

You can confirm that router uses correct flow duration using this command

Apply changes and restart daemon:

After this steps you need to configure Netflow / IPFIX on agent’s side (switch, router, server) to configured port.

We have detailed guides for following vendors: