I'm waiting for deliver of a Linksys EA3500 router.

I was wondering if it was possible to get the WAN port act as normal WAN port (Internet IP) + LAN switch ?

My problem is that my Internet box is in a room with NAS and PC, and the router will be in another room with TV, PS3 and PC.

The Internet box have a 4 port Gigabit switch so one cable will plug from there to the router's WAN in the other room.

The router will get the Internet IP from the Internet box, but will it be possible to have private network through this link too ?

I could have a first network between the Internet box and the router, and another network form router and devices but that will do double NAT for nothing...

Thanks for reading me and your help !