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PRTG Netflow

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With Netflow enabled and pointing to PRTG, the Netflow sensor in PRTG does not reflect the throughput seen on the normal SNMP probe of the same customer interface. There are no filters set in which would hamper the information. Running PRTG v8.

Can someone explain to me that the throughput on the Netflow probe in PRTG should match what is seen in PRTG for the SNMP data of the same interface port?

If not, why?

netflow prtg snmp

Created on Feb 3, 2012 3:03:33 PM



7 Replies

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Hello,

I'm afraid comparing Netflow Data with SNMP Data is always difficult. First of all, there is the active Flow Timeout which 'delays' the traffic monitored with Netflow a bit. Even more 'distraction' comes in if the Netflow is produced from an ASA which only sends information once traffic streams are terminated.

best regards.

Created on Feb 3, 2012 5:43:04 PM by Torsten Lindner [Paessler Support]



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We're calling SNMP numbers from our switch stack, and our Netflow data from the 7609 router, the router is capable of determining which port of the switch stack it pushes data through, no ASA involvement. A customer for example pushing 30mb through on the switch is instead seeing only 10kbps in Netflow.

Created on Feb 3, 2012 5:47:20 PM



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do you have any filters applied on the netflow sensor?

did you check the netflow configuration on your router? Make sure all data is included.

Created on Feb 5, 2012 10:41:16 AM by Aurelio Lombardi [Paessler Support]



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I have this same issue with both connections for NetFlow V9 and IPFIX sensors from Cisco router and SonicWall firewalls respectively - neither reports throughput for connections, just amount of data. The same Cisco router reporting to Scrutinizer does show throughput for connections, so I know the data is available. I just can't get either PRTG sensor present it, if it's taking it in at all.

Created on Jan 30, 2017 2:20:57 PM



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So the Connection Toplist doesn't show any bytes for each channel? Or do you simply need throughput information for each interface of the Cisco appliance?

If you need detailed information about the actual throughput, you probably want to add the SNMP Traffic sensors to the device which will show the same. Note that SNMP Traffic and NetFlow data can only be compared roughly. This means that the graphs may only be convergent, not exactly the same.

Created on Jan 31, 2017 11:38:14 AM by Stephan Linke [Paessler Support]



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I mean for any given connection or talker - such as a user's computer to a particular web or file sharing site - we want to see how much of bandwidth is being consumed. The byte count doesn't give us that info. And monitoring the device ports via SNMP is the total of all connections.

Created on Jan 31, 2017 2:09:37 PM



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Well the NetFlow Sensor can only give you the actual byte count, not the bandwidth consumed overall I'm afraid :(

Created on Feb 1, 2017 6:50:31 AM by Stephan Linke [Paessler Support]




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