Unknown devices popping up with BGW320-500

Factory reset the gateway and see if the devices show up again. I presume you have no other router connected to the gateway and few if any smarthome/Wi-Fi devices. 

Hi there, kolibri. We understand that you have some "phantom devices" appearing on your connected device page of your BGW 320-500 user page. We can look into that.

One of our coummunity ACE's, @browndk26,  gave some great information about factory resetting the AT&T equipment. The reason why you would want to do that as it clears the router and reverts it back to state when you first received it.

They also asked a question about having another router connected to the gateway. If you look at the pattern, most of the "phontom devices" are connected via Ethernet. Which means that something physically has to be plugged into Ethernet port.

Our recommendation is that you might want to go around the home and check for any devices that are connected via Ethernet. Some homes are even wired for Ethernet throughout the home, that means that even a desktop computer that doesn't have Wi-Fi can connect to the internet  via Ethernet, to a port in the wall. Another way of looking at this is, to think of a hotel room.  Most hotels offer free Wi-Fi for their guests, but they also offer an Ethernet connection in the hotel room.

Also, do you have AT&T U-Verse TV? Some of the U-verse cable boxes are Ethernet capable. The reason why we bring this up is that sometimes those devices will be "unkhown" when registered to the router, but they will show as connected.

So try the factory resetting first and let us know if that clears up the "phantom devices".

Matthew, AT&T Community Specialist

Yes, I did a factory reset last night and it did not help. There are a couple of things to note. After the reset I changed the subnet to 196.168.2.% from 192.168.1.%. Also, I do have two other routers connected to AT&T's router, however they only act as wireless access points and switches and perform no actual routing functions.

Yes, there are Ethernet outlets in every room. They are all wired to the "central" location where AT&T ONT/router is. There is also a switch there since I have more rooms that there are Ethernet connectors on the router. Two additional are in two room where I have more devices connected to them, but again they really only act as switches.

no, I do not have U-Verse. But even if I had one, it would have probably been a singe unknown device in the list. In my case these unknown devices keep proliferating like rabbits which I do not consider normal at all.

In any case, browndk26 mentioning other routers gave me an idea. I disconnected most of the devices and with the remaining few I did not see these phantom devices. I am connecting them one at the time now (time permitting) and I expect to identify the culprit this way. I shall report here what happens at the end in the interest of public knowledge.

I have identified the problematic device - it is Tesla solar panel "gateway". It seems that it keeps requesting an IP address using a different MAC every time. I suspect it exhausted the previous gateway of available IP addresses to give out to a new device and that there was nothing actually wrong with it. I may have had a perfectly functioning device replaced thinking it was the one that broke.

For those extra curious, here is another interesting bit I have learned along the way. As I was connecting the devices I kept track of their IP and MAC addresses. I found that the MAC address for an Android phone reported by the router does not match one reported by the phone itself. I have learned that Android phones randomise their MAC addresses, however I would expect that it reports the actual one for the current connection.