I have one AEBS, one AXBS and one AX (older generation).
The Cable Modem is connected to the AEBS WAN input and the ethernet connection from the AEBS is connected to port 1 on the Netgear FVS318G. Ports 2-8 of the Netgear are distributed to seven locations througout the house via Cat 6 ethernet cable. I originally had the the ethernet output from the AEBS connected to the WAN input of the Netgear FSV318 but had to change it to ethernet port 1 of the Netgear to make it connect to the AEBS. I originally had eight locations connected by Cat 6 ethernet cable throughout the house.
I inserted a Netgear switch (GS105) to make up for the loss of the one Netgear FSV318 ethernet port used when I couldn't use the WAN input on teh FSV318. This was to make sure that all eight original distribution points still have an ethernet connection. Attached to the remaining ports (2-8) are a Mac, a PC, two Apple TVs and the third, legacy AX or nothing at all (3 locations).
The Netgear FSV318 LAN TCP/IP Address was changed to 10.0.1.100 (factory original 192.168..1.0)
The Netgear FSV318 Starting IP Address was changed to 10.0.1.2 (but shows as 192.168.1.2)
The Netgear FSV318 Ending IP Address was changed to 10.0.1.100 (but shows as 192.168.1.100)
I then disabled the DHCP Server onn the Netgear FSV318.
AEBS IP address is 68.8.47.200; LAN IP Adress is 10.0.1.1
AXBS IP Address is 10.0.1.9
The legacy AX shows missing using the Airport Utility. I substituted the AX at the same location with the AXBS but it still shows missing even thought the AXBS works. I test for wi-fi bandwidth down and uplinks with an app on my iPad.
Hope this clarifies things for you.
Steve