Strange unknown Windows devices "not in network"

pkirsche Member Posts: 7
First Comment Photogenic First Anniversary
edited April 2, 2021 in Devices & Security #1
Hello Fing-Community,

after analysing and messing around with a strange behavior of my fing box I am now at a point where I don't know any further.
Since a few month, several unknown devices appear on my network (LAN and WIFI) which are identified as "Computer" running "Windows".
The devices itself don't seem to be connected to my network, none of them has ever had a correct IP-address, they are showing up in fing with these details (one of the several entrys as an example) 

IP address: not in network
MAC address: 00:65:8B:90:09:2C

Other devices are having MAC addresses like:


If I check these MAC address, it only tells me that its an unknown OUI. So I assume these MACs are randomly generated.

New devices appear multiple times a day and are filling up my network device list. Only workaround actually is to block new devices per default by fing. But this leads to a mail and notification for every of these ghost devices when they are blocked. I don't want to disable notification at all as this is one of the major features to tell me about "real" new devices on network.

I already resetted my fingbox, deleted the network, used another ethernet cable but none of that did make any differences. 
Day after day I have to delete these unknown devices.

Has anyone else this issue with fing? Is there any solution or idea?
Help is much appreciated.