Hello Valerio
The error message you’re receiving indicates that Observium is detecting a conflict. It seems to be identifying the second IP address as belonging to a device that it’s already monitoring.
A possible workaround could be to try and add the second IP address as a new device but with a different sysName. This might trick Observium into treating it as a separate device. However, this workaround might not be ideal as it could lead to some confusion in your network monitoring.
Another option would be to check if you have SNMP correctly configured on both IP addresses. If SNMP is not correctly set up on the second IP, Observium might not be able to recognize it as a separate entity.
In any case, if you do try out LibreNMS, you may find that the problems you are facing will be resolved. Let us know how you get along!
I hope this has been helpful!
Laz