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Netflow sensor not receiving data.



I have a cisco router exporting netflow data on UDP 9509.

I have set up the sensor and it is not receiving data.

I made firewall exclusions and then even disabled the firewall, but no joy.

I have used the netflow tester on UDP 9509 and it shows data.

I'd expect the netflow tester to error when I load it without first stopping PRTG. It doesn't.

So I did a netstat-ano and I cannot see anything it listening on the udp9509. So the sensor seems not to be running. I restarted the probe service and rebooted the machine, still not listening.

netflow-v5 netstat no-data

Created on Oct 3, 2017 3:35:54 PM

2 Replies



I set up a netflow v9 sensor on a different router and it worked.

I altered the channels by setting a coup[le to no and one to detail and it stopped working.

I set them back again and it still won't work.

I deleted the sensor and re-added it and it won't work.

I n my previous post, I didn't mention that I had set some channels to 'detail'

Is this a bug or am I doing something wrong?

Created on Oct 20, 2017 1:21:39 PM



Hi John,

I'm very sorry for the delayed response. It's entirely my fault as I seemingly closed the corresponding ticket without the reply posted. Sorry about that! It surely does not reflect our support quality.

We usually respond to the questions posted within the forums within 24h at least, but this was surely an honest mistake. Please accept my apologies for the less than stellar support experience received.

As for the question, could you please post a screenshot from the Netflow Tester that shows the incoming data? Feel free to obfuscate IP addresses if necessary.

Kind regards,
Stephan Linke, Tech Support Team

Created on Oct 23, 2017 10:13:48 AM by  Stephan Linke [Paessler Support]

Last change on Oct 23, 2017 10:13:57 AM by  Stephan Linke [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.