Question Strange device in local network

[Justanotherproblem]

Hello
I have a strange device in my local network that i discovered with ip scanner. This device is not visible in my routers web interface. My routers ip is 10.0.0.138 and last digits of mac address is 66. The device i found have ip 10.2.0.138 and last digits of mac is 67. It has same manufacture name as my router but is also named "localhost". It wont respond to ping. Its also visible in the app "Wifi Thief Detector". It connect and disconnect at various times. Right now its not online according to app. Its also visible in Wireshark but i am totally green on how to read all the information there. Also im using powerline adapter and range extender connected to it. I notice in the ARP table if i turn on my phone wifi which goes through the range extender the device change its mac address to be identical with routers mac address (66). And if i turn off wifi its mac change back to 67.

 

[bill001g]

What is the lan IP on that router and what is the mask.

Maybe change the lan IP to something more common. Try using say 192.168.1.1 with a mask of 255.255.255.0.

It is hard to say why the router would have multiple IP and mac addresses. I have seen this on commercial layer3 switches where every logical interface uses a different but very similar mac address.

Finding any form of documentation on that device is close to impossible, likely it is not in english so google doesn't find it.