Wired and wireless network via Comcast using RT-AC66W with latest firmware... Network has been working as expected for years. All of a sudden, data usage went through the roof for about a week (the last week of the month), and the network used 3/4 TB of data, throwing me over the Comcast 1TB cap. Using the "Traffic Manager," I can see data downloading at a steady 1500/1600 KB/sec at this moment, but I have no idea which of the 25 or so computers, phones, printers, NAS boxes, or IoT...
[RT-AC66W] Determining data usage by device
[RT-AC66W] Determining data usage by device