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No such instance (SNMP error #223) - Multiple issue



Dear all,

We recently upgraded all of our Cisco Switch. We have restarted them and since then we have 30 sensors that no longer work in PRTG, With the following error message: No such instance (SNMP error #223)

I've seen in your knowledge base that for ports, this comes from the fact that the port number has changed. But how to find the right number? And how to change it in the sensor settings?

I have the same problem for other sensors: System Health Alimentation System Health Tensions System Health Courants System Health Autre

I do not know PRTG well, can you help me?

Many thanks.

Best regards,


cisco-3750 sensor snmp

Created on Apr 6, 2017 3:28:06 PM

3 Replies



Hi Kevin,

For traffic sensors, this indeed happens if the internal indices change. For Cisco devices, you can follow this guide to set the IfIndex Persistence. This will prevent the changes in future updates of the device.

You can find the correct OIDs and indices by performing SNMP Walks, the OIDs of the traffic sensor are listed here. You can manually change the interface number in the settings of each traffic sensor. Simply click on the grey box and exchange the number. Note that you need to be sure that you enter the correct number. Otherwise the wrong data will be shown.

For the system health sensor it will be required to add the sensor anew since the indices cannot be adjusted manually.

Best regards, Felix

Created on Apr 10, 2017 11:26:01 AM by  Felix Saure [Paessler Support]



Hello, was this issue resolved? we face some issue like this, randomly the sensors return error (SNMP error # 223) even when the OID has not been changed even worse the snmp walk tool return same issue when a query is ran. any idea how to address this issue?

Regads. Milton.

Created on Apr 25, 2019 3:27:30 PM



Hi there,

The issue has little to do with PRTG, the error message literally means that the OID requested is not available on the device you query. Might be worth to run a walk against the OID, maybe you are missing an index in the end of the OID.

Best regards.

Created on Apr 26, 2019 6:54:19 AM by  Dariusz Gorka [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.