SNMP Discovery failure (badValue)

Troubleshooting
,
1

Hey everyone,

I’ve been experimenting with checkmk for a couple weeks, and have a few basic monitors set up. This weekend I decided to try setting up one of my UPS units in the software (old Tripp Lite WEBCARDLX based). I’m very much a novice when it comes to checkmk and SNMP in general.. so please forgive me if I’m using any of the wrong terminology!

The problem I’m running into is the Check_MK Discovery fails with the following:

SNMP Error on 10.2.0.205: Error in packet.
Reason: (badValue) The value given has the wrong type or length.
Failed object: .1.3.6.1.2.1.1.3 (Exit-Code: 2)

Doing a snmpwalk directly results in nearly the same error:

iso.3.6.1.2.1.1.1.0 = STRING: “Ubuntu 18.04 Linux 4.4.31 flash: 3.34G ram: 506844kB processor: armv7l software: PowerAlert 20.2.1 (Build 942)”
iso.3.6.1.2.1.1.2.0 = OID: iso.3.6.1.4.1.850.1.1.1
Error in packet.
Reason: (badValue) The value given has the wrong type or length.
Failed object: iso.3.6.1.2.1.1.2.0

I’m already monitoring this UPS using PRTG without any problems, so I do know the OID I’m specifically interested in (1.3.6.1.4.1.850.1.1.3.3.3.1), and I’m able to run snmpwalk without problems if I give it a specific OID starting point such as 1.3.6.1.4.1.850.

It looks to me like this almost certainly the fault of the device (not checkmk!), but I’m at a bit of a loss as to how to proceed. So I guess my question is.. what is the best way to deal with this? Can I configure checkmk to monitor a specific OID directly without running the discovery? Is there anything I can do to make checkmk skip over the problematic objects?

Thanks in advance for any suggestions!

CMK version: 2.5.0p3
OS version: Ubuntu 24.04

2

Hi @bfaler,

this could have a lot of reasons, why it isn’t working as well. But the most likely reason is, the SNMP implementation of the vendor.

But to troubleshoot this better, you can have a look at this guide:

Regards,
Petra

3

Thanks. Interestingly, I just logged in to set up a monitor on a different machine, and now all the sudden the device discovery has apparently completed with at least some success automatically, as I have several services showing as unmonitored! It still isn’t showing the actual services I do want to monitor.. but it is at least showing some SNMP data! I’ll take a look at the linked guide and see if i can figure anything else out!