What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

Netflow from multiple routers



When I enable net flow for multiple router using the same UDP port 9993 the collection stops to work, once I change the port of one of the routers to 9994 the collection resumes. Christian Lamparth

netflow netflow-v5 netflow-v9

Created on Oct 24, 2012 2:54:31 PM

3 Replies




does the sensor go into an error state then? Or in unknown state? Which version of PRTG have you running? Is it ensured that only the same Netflow Packets (in terms of netflow version) are sent? Do you by any chance get any ToDos from PRTG about the issue?

best regards.

Created on Oct 25, 2012 2:33:58 PM by  Torsten Lindner [Paessler Support]



Hello Torsten, We are using verison 9.1.3 with netflow verison 5 what I just noticed is if I have two routes A and B and both of them have netflow senors configured if i change the port on of one those two sensors the other sensors port get changed as well. ex I change the port for netflow sensor a to 9994 the port for netflow sensor b is also changed to 9994, it is ok for me to use the same port for both routers but how can i seperate the traffic in this case?

Thanks Christian

Created on Oct 25, 2012 2:56:26 PM



There should be a "Sender IP" field in the Settings of the Netflow Sensor, and this can be used to filter only for Netflow Packets from one certain IP.

Created on Oct 25, 2012 6:01:10 PM by  Torsten Lindner [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.