So I just picked up a new RPI and I was wanting to make it in to a home router but had a few questions I was hoping to get answered. I have looked around already but was unable to find an answer. My goal was to take my DSL modem and connect it to a wireless router that is running DD-WRT and turn it in to a acesspoint/switch. From there i would connect my PI in to the second lan port and have it manage all the network stuff like dhcp and firewall. From all the guides I have seen they all talk about using a wireless usb adapter or using a usb nic. I really was hoping i would be able to have everything route to the PI then have it route it back out to the network using just the onboard nic. IE kind of like how you can set up many virtual vlans off 1 nic in a switch.
DSL MDM ----AP/Switch ----PI(DHCP Server/Firewall/NAS)
I know its a crude network diagram but i think it should work.