Do you happen to have a Firepower SFR module between the PRTG server and the subnet that has issues?
If so, then it *might* be the same problem as in this discussion: https://supportforums.cisco.com/discussion/13294256/how-exclude-network-monitorin...
Have you tried using Paessler's "netflow tester"? It's a simple netflow receiver that you can use to see if the flows are arriving at the PRTG server at all.
If you don't see any flows in the test tool, then the problem is either with the switch or ...
This usually means that either SNMP isn't enabled, or (more likely) that something between the Cisco device and the PRTG server is blocking SNMP.
Does SNMP work with IPv4? So you can narrow down the problem to IPv6? Or do you get the same error wit...
It's not really the netflow or the PRTG configuration -- it's a question of where you're collecting the flows.
The results you're seeing are from flow records generated on the router between HQ and the remote site. However, the traffic has already be...