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QoS Probes not processing data



We have two probes running on separate PC's using the QoS both way sensor. Although we can see the Source and Destination IP Addresses and relevant Port appearing to be OK in Wireshark, PRTG is indicating that no data has been received. Any ideas?

probe qos sensor

Created on May 15, 2013 2:55:55 PM

5 Replies



From a command line prompt, please check with "netstat -ano" if the corresponding PRTG probes have succesfully opened an UPD port on their computer.

Created on May 17, 2013 9:04:26 AM by  Patrick Hutter [Paessler Support] (7,225) 3 3



I've got two roundtrip QOS sensors running to remote probes at different network locations. I''ve been seeing behaviour where the sensors would just randomly stop receiving data from the endpoints. Initially I thought this is caused by some firewall or ISP network throttling - but the most recent event both sensors simultaneously stopped receiving data at the same time.

When I click the "check now" button on each sensors it seems that they resume again.

Any ideas as to what may cause this, or how to troubleshoot why the sensors will just stop?

Created on Nov 16, 2015 5:14:21 AM



Hello cronjevh,
thank you for contact.

Please make sure that you're running the latest version prior to any testing.

The best way to identify what is happening (if packets are leaving the source probe and reaching the destination probe) is using Wireshark. The packet capture performed by Wireshark will allow you to see the UDP traffic generated by the sensor.

Best Regards,

Created on Nov 17, 2015 11:39:33 AM by  Luciano Lingnau [Paessler]



I've experienced this now (beleive I have in the past too). To probes in different subnets connecting to core server. Installed wireshark and confirmed that both probes are sending UPD packets back and forth that is received by the core server.

Both QoS sensors claim not receiving data. Now what?

Created on Nov 7, 2019 7:56:51 PM




What version of PRTG are you currently running? If your already on PRTG's latest stable ( please consider contacting us directly via email at [email protected] as it will be mandatory to check your current configuration more in detail, which is much easier via email than on our KB.


Created on Nov 8, 2019 6:56:13 AM by  Sebastian Kniege [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.