I'm completely stumped here... I have a D6400 modem/router which I've used with BT infinity VDSL2 for years. I've just bought an ASUS RT-AX92U router.
So, I've set the D6400 to MODEM mode only, and it's currently synced on the line.
I've checked the manual and don't have a clue which PORT on the back of the D6400 I need to connect the WAN port from the ASUS model to. I'd presume it goes ASUS WAN Router port -> Netgear D6400 LAN Port??? < which port, or does it not matter ???? Has anybody on the forums here used a D6400 in modem mode before??
I've searched the Net and found literally nothing about my setup, except for one guy on PlusNet who got his Netgear Orbi router working with the D6400 in modem mode.
Now, MAKE damn sure at the bottom of the WAN config page in the ASUS router's GUI that you have a MAC ADDRESS listed. IF IT IS BLANK click CLONE MAC button then apply... Your internet will then work if your PPPoE user/pass credentials are correct!!!