I  want the WDR3600 router to act as a wired switch for my wired connections. I have configured my router in "access point'' mode. (wireless radio is off)

Setup: Modem - - - Deco (master) - - - WDR3600 AP mode - - - Deco (slave)

I have set the LAN IP in the Deco DHCP range and disabled DHCP server. 

Do I also need to disable NAT and disable Hardware NAT or not? 

Do I need to change any other settings (eg. firewall) to faciliate this? 

Thanks