Forum Discussion

Justin_Lanoue's avatar
25 days ago

Network Interface - Duplicates/Nulls

Is there any solution for when network interfaces get assigned a brand new ID or become null and have a duplicate ID?


This seems to have every so often across our clients where Ge1/0/2 will go from ID 10 to ID 150 randomly maybe after a firmware update or something.

You would think LM would be smart enough to merge these togethers or not create a duplicate null ID 10 when it exists already.

I guess I could filter out null instance names in the discovery but that doesn't resolve the ID change on interfaces.

4 Replies

  • LM creates a duplicate because that logicmodule doesn't have the "use the wildvalue as the unique identifier" checked. Which means that it doesn't just use the ID as the key for that object, it uses the combination of the id and they name. Same id but different name? LM treats it as a separate object. I'd like to see LM go through all their legacy modules and identify which ones can safely switch over to the new ID method and make the change. It wouldn't take much to evaluate a couple modules a week and push the change. It would also get/keep their "we push out updates very often" numbers up.

  • Hello Justin_Lanoue, I hope this finds you well! A recent update to the "Network Interfaces" (SNMP_Network_Interfaces) module has addressed this concern.

    As Stuart_Weenig has shared, you generally want ifindex persistence for SNMP enabled on your devices to prevent this, but in general, the IDs changing for interfaces can indeed cause the issues you are seeing.

    To address this, add the property interface.wildvalue.ifname to your resource (or group of resources), and set the value to true.


    This will help avoid concerns with changing interface indexes. Please update your datasource, and give it a try! 

  • I don't have an answer myself but it's been brought up a few times in this community, for example at

    • Stuart_Weenig's avatar
      Icon for Mastermind rankMastermind

      You should have `snmp ifindex persist` in your config to ensure that IDs don't get shuffled on reboot or when an interface is added.