This article applies as of PRTG 22
Setting ifindex persist directly on the device
You can set "persistence" for interface numbers globally or at interface level. The global command does not override local settings, so you may need to modify the interface-level settings. So when you applied the ifindex persist command on your switch or router, did you apply it at global level or at the interface level for each interface?
Depending on the IOS (Internetwork Operating System) version of your device, the command to globally enable persistence is:
snmp-server ifindex persist
snmp ifmib ifindex persist
To determine your current settings, run the following command on your router or switch:
show snmp mib ifmib ifindex
show interface snmp-ifindex
If necessary, change the settings of particular interfaces with the ifindex persist command.
To debug issues with persistence, run the following command on your switch:
This command will give you a result that looks like this:
Router # dir nvram:ifIndex-table
Directory of nvram:/ifIndex-table
2 -rw- 0 <no date> ifIndex-table
126968 bytes total (114116 bytes free)
If you see a zero in the middle of the output, you may have forgotten to run copy running starting. If so, copy the running config into the startup config and run the dir nvram:ifIndex-table command again.