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What to do about "Could not find a table row matching the index you specified when adding the sensor

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Hello,

So recently I started monitoring a few Cisco WLC's using the template provided in the relevant kb post. Everything seemed to be working quite well at first. However, over last weekend the error "Could not find a table row matching the index you specified when adding the sensor" occurred about a 100 times. All sensors eventually returned to a normal state. I've encountered the same problem with the monitoring of the VPN tunnels of a checkpoint firewall using a custom snmp table. When I keep on rescanning the sensor manually, the error eventually goes away,.

The weird thing is that I also use around 150 sensors (snmp custom table) per F5 load balancer to monitor things like virtual servers, pool members etc. without experiencing the same error.

Some more info: License: PRTG Unlimited Sensors: 5100 Hardware: VM 16 GB Ram 8 CPU cores SNMP: V3

Scanning Interval WLC AP: 10 minutes Scanning Interval Firewall: 120s

Thank you.

error-pe247 prtg snmp-custom-table

Created on Jul 15, 2019 7:15:23 AM by  Netwerkbeheerder01 (0) 1



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Hi there,

I am afraid that there is no real solution to that :(

For PRTG it is an error that should be reported to the user, as PRTG is unable to retrieve the data. The only workaround, which would require some work, is to write a custom script (e.g. in PowerShell) that queries the data and ignores these errors:
https://www.paessler.com/manuals/prtg/exe_script_sensor
https://www.paessler.com/manuals/prtg/exe_script_advanced_sensor

Best regards.

Created on Jul 16, 2019 7:50:16 AM by  Dariusz Gorka [Paessler Support]



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Hi there,

At the times, when the sensors throw these errors, are you able to manually walk the monitored OIDs via our SNMP Tester?
https://www.paessler.com/tools/snmptester

Best regards.

Created on Jul 15, 2019 8:49:41 AM by  Dariusz Gorka [Paessler Support]



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Hi Dariusz,

I've tried what you suggested and indeed I am not able to walk the monitored OID's when this error occurs. Which is quite a shame, because the monitored things do indeed come back up eventually and then they are reachable by snmp-walk at the same index still.

The only solution I see at the moment is to somehow disable error PE247, but I have no idea if this is possible. Right now I am using a http notification trigger to immediately acknowledge when the sensor goes into an error state. Obviously this is not ideal, because I am not able to discriminate between error PE247 and all other events that cause the error to happen. A more suitable solution would be preferred, if there is any.

Thanks.

Created on Jul 16, 2019 6:59:42 AM by  Netwerkbeheerder01 (0) 1



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Hi there,

I am afraid that there is no real solution to that :(

For PRTG it is an error that should be reported to the user, as PRTG is unable to retrieve the data. The only workaround, which would require some work, is to write a custom script (e.g. in PowerShell) that queries the data and ignores these errors:
https://www.paessler.com/manuals/prtg/exe_script_sensor
https://www.paessler.com/manuals/prtg/exe_script_advanced_sensor

Best regards.

Created on Jul 16, 2019 7:50:16 AM by  Dariusz Gorka [Paessler Support]



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Hello, We have just implemented PRTG and I am in the process of adding one of our many WLC's. I have added the Cisco+WLC+Templates+v0.2 from the previous KB, restarted the core service and added the WLC.

The issue is that all AP's connected to that WLC are showing down with error message "PRTG could not find a table row matching the index that you specified when adding the sensor (196.20.60.40.168.32). The reason might be that the value of the column that you selected has changed. (code: PE247)"

I've left it for 2 hours and the status is still the same.

WLC is 5508 running 8.5.151.0. AP's are AIR-CAP3602I. PRTG is version PRTG Network Monitor 20.4.64.1402 x64

Created on Jan 21, 2021 4:32:05 PM by  Rocky (0)



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Hello Rocky,

The issue is caused by a bug, due to which the sensors are not added properly. This will be fixed in the next stable version 21.x.65. (should come out by the end of January).


Kind regards,
Sasa Ignjatovic, Tech Support Team

Created on Jan 25, 2021 1:21:09 PM by  Sasa Ignjatovic [Paessler Support]



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