I now have a ATT fiber ISP with it setup as PassThrough.
The ATT Router is 192.168.1.254
The Orbi Router on Advanced Internet is setup with the following:
Internet Setup TAB
IP 192.168.1.1
Mask 255.255.255.0
Gateway 192.168.1.254
An it keeps changing the IP back to 10.0.0.1 WHY??????
Wneh the WAN (internet) side of the Orbi has an IP address of 192.168.1.x, then it automatically sets the LAN IP subnet to 10.0.0.x
(Yes, in theory any of the 192.168.x subnets (bwesides 1) could have been used, but Netgear chose to change to the entirely different private IP space.)
My guess is that the ATT fiber unit is not set to bridge or passthrough mode.
OR... (because I know so little about AT&T), it could be that AT&T has so many customers that they are unwilling to waste a precious public IP address on every one of them, and have set up a router "upstream" to NAT them all from different subnets to the one public IP. The fiber ONT may simply be passing along the private subnet IP. If this is the case (a big "if" because of my lack of knowledge) then it will be impossible to do any activity that is broken by a Double NAT (OpenVPN, forwarding any ports, certain types of internet gaming, etc.)
https://whatismyipaddress.com/ will display what your public IP address is, and this is what should appear on the WAN side of the Orbi.
Re: RBR50 automatically setting up as a 10.1.1.1 subnet
Using 10.0.something isn't a bad thing either. Just your ATT Modem uses .1.1 on its LAN and does the RBR. So the RBR moves to 10 to avoid conflicts. You can set the RBR to use .0.1 or even you can change the modems IP address to use .0.1 and then you can set the RBR to .1.1 if you want to.
