@Curtis11 Does it come online automatically? How are the satellite Decos connected? Are you running the Deco in Router or AP mode? Does your modem act as a DHCP server?

@SKane9 You could use a "lan scan" software, it will perhaps provide more details about that device.

@KFB What is you existing setup? If you simply want to add a Deco mesh to a working installation based on the AT&T box, to extend your wifi coverage, you could simply configure the Deco in Access...

@SKane9 If you want to prevent that device from connecting to the Deco, why do you delete it instead of keeping it blocked? . The Deco displays the MAC address of the device. From that address, you...

@DennisRatcliffe Do you mean you have a Windows computer unable to stay connected to the Deco? Is this a wifi or Ethernet connection?

@gec5741 This poe switch is a low speed switch, with a max speed of 100 Mbps. It is perhaps negociating a speed of 10 Mbps, either with the Deco, either with your main switch. I would run the Deco in...