I have a Linux device that is monitored through SNMP. The device is correctly discovered.
At first I had some issues with the VPN interface (OpenVPN) that was related to the IfIndex. After searching the forum, I changed it to IfName and everything was solved; although I thought is was.
Now it seems that when the OpenVPN is disconnected, the interface (called tun0, during discovery) ‘disappears’ from the GUI in LibreNMS, but under Inventory it says it is still running.
When i connect the OpenVPN again on the Synology, the tun0 interface appears again in the interface.
Now how can i monitor the interface when it is disconnected? It disappears every time, and i can’t build a alert rule that detects a disappearing interface.
Here you can see it is connected and correctly dicoverd and all
But here the VPN is disconnected, disappeared from the monitoring but in inventory still running?
Also in the Eventlog of LibreNMS, nothing is noticed regarding the tun0 interface.