Even so, if you wish to make use of a router guiding your ISP's box, It's not necessarily necessary to provide the router mode enabled on the current configuration. Here are a few samples of how diverse router modes and switches would assign IP addresses to computers inside a network. https://customer-care-support-number.com/how-do-i-reconnect-my-netgear-wifi-range-extender-to-my-home-network-5/