Setting up NetFlow Collectors

In order to use NetFlow monitoring you must set up a NetFlow Collector in PRTG. This instructs PRTG to accept NetFlow packets from the router coming in via a specific UDP port. The same IP and port must also be configured in the router configuration.

Using the menu item Extras|Netflow Collectors you can edit the setup for the collectors:

If you have purchased additional NetFlow Collector Licenses you can enable them by clicking on Add License:

Simply copy the license key(s) into the edit field and click OK. You should now see the corresponding number of NetFlow Collectors in the Licenses List.

Click on Add to create a new NetFlow Collector:

Here one can define the name of the collector, the local IP address, the local port, and the active flows timeout value.

Except for the name these settings must exactly match the configuration of your router. Please see the section Configuration Tips for Cisco Routers and PRTG (NetFlow/SNMP) for more information.

Have a special look at the last value (Active Flows Timeout). For non-high traffic situations (<10 MBit) a recommended value is 5 minutes, for higher traffic scenarios higher values of up to 30 minutes are recommended. This value has to be configured in the router!