Unknown device showing up on my offline devices of router, connected via Ethernet

BasedThot

This is driving me nuts. Was messing around with settings today on my router and found this unknown device in "Offline Devices" and that it connected via Ethernet and have no clue what it is. Did a MAC look up and it's an Apple device. What could even be an explanation?? Someone broke into my apartment and connected to the router with an RJ45? I recently got an iHome GlowPlay Portable Speaker + LED Lighting but I wouldn't think it'd connect to the router and even if it did I played around with it as much as I could and it wouldn't reconnect to it. Recently connected my HP Notebook via an RJ45 to the router, if that provides any useful info but all I did was a speed test.

JDMurray

Is your router a switch too? A device "connects" to a switch at Layer 2 by sending just one frame that puts the source MAC into the CAM table. Is it possible that someone tried to cable-connect a MacBook to your router to get Internet access? Does Apple publish a list of its OUI blocks that identify which Apple device would/could be assigned that MAC address?

BasedThot

JDMurray said:

Is your router a switch too? A device "connects" to a switch at Layer 2 by sending just one frame that puts the source MAC into the CAM table. Is it possible that someone tried to cable-connect a MacBook to your router to get Internet access? Does Apple publish a list of its OUI blocks that identify which Apple device would/could be assigned that MAC address?

Yeah, it's also a switch. It's not possible someone tried to cable-connect a MacBook to my router for internet access unless they broke in while I was gone, left without a trace and stole nothing. I'll have to try to find OUI blocks 

BasedThot

So upon taking a closer look, when typing the MAC address into a different lookup it comes back as an LAA,"the address is assigned to a device by a network administrator, overriding the burned-in address." Making things stranger still

JDMurray

Some devices have the capability of using a software-configurable MAC address (aliasing) to be used in place of the burned-in MAC address (BIA) that's encoded in the device's NIC hardware. Network routers and Wi-Fi Access Points can be configured to use a source MAC address alias. Might you have plugged anything in to a switchport that supports MAC aliasing? 

BasedThot

JDMurray said:

Some devices have the capability of using a software-configurable MAC address (aliasing) to be used in place of the burned-in MAC address (BIA) that's encoded in the device's NIC hardware. Network routers and Wi-Fi Access Points can be configured to use a source MAC address alias. Might you have plugged anything in to a switchport that supports MAC aliasing? 

Yes! I did plug in my HP laptop into the router yesterday to conduct a speed test. However I can see entries for the HP laptop for both the WiFi and Ethernet connections, they both have different MAC addresses but none of them match the address of the unknown device