I have a Cisco switch with a System Health Fan sensor on it. Sometimes it appears that the sensor stops working with the following error message:

No such instance (SNMP error # 223)

The only solution I have at the moment is to recreate the sensor fresh, and delete the old one. However this then removes the history on the sensor which isn't ideal.

When looking carefully at the content of 'PRTG Configuration.dat' and comparing the old sensor vs the new sensor, I can see the following OID that is created differently in the new sensor.

Old Sensor:

<name>
  System Health Fans
</name>
<oids>
 1.3.6.1.4.1.9.9.13.1.4.1.3.1035&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.1037&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.2035&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.2036&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.3055&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.3083&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.4047&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.4057&#x0d;
</oids>

New Sensor:

<name>
  System Health Fans
</name>
<oids>
  1.3.6.1.4.1.9.9.13.1.4.1.3.1035&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.1036&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.2035&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.2036&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.3034&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.3064&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.4034&#x0d;1.3.6.1.4.1.9.9.13.1.4.1.3.4048&#x0d;
</oids>

The difference is in the oid on the new sensor.

My options appear to be varied, and I would be keen for which one might be the safest option.

1) Find a way of moving the historical data from the old sensor to the new one. Various threads on this, explaining that its not supported (Bad).

2) Edit the 'PRTG Configuration.dat' file directly and save the file. However we are a 24/7 shop, so taking down the server to do this would be a bit of a nightmare. I don't know if there is a way of stopping anything in PRTG from writing to the file while I do the work, and then trigger some kind of reload once I have done the work. Just need to adjust the OID.

Article Comments

Hi Richard,

Please check this site if your firmware is in the list that is affected by the bug. Is this the case?

Best regards.


Feb, 2017 - Permalink

Thanks for the info, but no. In this case the device is a Cisco 3750 - 12 Port Switch


Feb, 2017 - Permalink

Hi Richard,

Unfortunately, the device itself doesn't matter. What firmware is currently installed on the device? :)


Feb, 2017 - Permalink

Good point.

Checking the device impacted, it is running 15.2(4)E1. I can see that 15.2(4)E is listed as a known fixed release, but 15.2(4)E1 isn't listed in either the known affected or known fixed. I would suspect that if 15.2(4)E is fixed, then 15.2(4)E1 would be as well.


Feb, 2017 - Permalink

Hi Richard,

Please try to update the firmware of the device anyway. Should this not work either, I am afraid that we are unable to do anything about it as it is unclear from our side why the indexes are always changing after a reboot, maybe this is better question for Cisco.

Best regards.


Feb, 2017 - Permalink

Thanks, I will discuss with Cisco and see what they have to say about it.


Feb, 2017 - Permalink

Did you ever find a solution for this. I'm having the same issue with my HP servers. The OIDs change after reboot.


Mar, 2018 - Permalink

Hi Michael,

Unfortunately, this thread is about Cisco which is a different story.

Therefore please open a support ticket under support@paessler.com and describe the issue you have together with screenshots of the sensor settings and overview page (where the channels are displayed).

Best regards.


Apr, 2018 - Permalink