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Subnet Traffic Monitoring



I have setup the PRTG on one subnet and monitoring the switch on another subnet that is not local to my location. As I added the Netflow v5 sensor it provides me with Information that is useful when I need to view the top talkers as well who is going where. However the Cisco device also gives me information of other subnet traffic that I should not be seeing. In fact if for example I am monitoring 10.5.1 as the source location why would the netflow send me source IP of 10.3.1 to destination IP 10.17.1? I have many others but this would be an example that I noticed on the top talkers. If I connect to the switch and view it via putty it does not show me any thing other than source IP as 10.5.1 to different destinations. Have you seen this before or has this been seen by others as well?

ip-address subnet switch-cisco

Created on Dec 19, 2012 7:56:59 PM

1 Reply




could it be that other Netflow devices are also sending flows to this sensor? PRTG definitely does not 'invent' flows. You can try just filtering for the one Sender IP in the sensors settings. Does this reduce the flows?

best regards.

Created on Dec 20, 2012 10:34:43 AM by  Torsten Lindner [Paessler Support]

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