No, what you're talking about won't work. The one Ethernet port on your modem is a connection to the public internet, and your service provider will only give you one public IP address via that port. Normally your router takes that one public IP, and then all your other devices connect to your router, and the router passes all the traffic through that one public IP. Think of it like apartments: there's only one "323 West Elm Street" but dozens of apartments (analogous to your devices, with their private IP addresses) route their mail through that one address. This is called Network Address Translation (NAT) if you're curious.



What you'll want to do is connect a router to your cable modem, then connect a switch to the LAN side of your router. That way all the devices that connect to the switch will have their traffic managed by the router.



If you have issues with WiFi with this setup because of the physical placement of the router and modem, you can add another "router" and put it in access point mode and connect it to the switch. What we call a "router" is actually a router, switch, wireless access point, and DHCP server (automatic IP address assigner). Most routers have the option to turn this off and just act as an access point. An access point is essentially a wireless switch.



Hope this helps!