arris bgw210

I have ATT fiber, which is terminated by an ONT box and an Arris BGW210 router. ATT insists I use the Arris router, which is a BEAR to work with. In order to use my own router, I put the Arris in pass-through mode and connected my Netgear Nighthawk's WAN port to a LAN port on the Arris. After a...