Currently I have a DSL modem plugged into an 8 port HUB. From the HUB I have one line going into the WAN of my Asus RT-N16 and one to the LAN of my Asus RT-N16. The other 5 ports on the HUB are all in use, as well as my the remaining ports on my Asus RT-N16. I'm using this configuration, because I also a phone adaptor that I want to connect it's WAN to over the DSL modem using PPPoE. The routing on tomato USB is smart enough to eliminate potential loops, so this configuration works perfectly. However, it occurs to me I could probably do in software the same thing by bridging the LAN and WAN together on the Asus RT-N16, then there would be no need for second cable to the HUB, freeing up both one more LAN port on my Asus RT-N16 and one more port on my HUB.
Before I start digging into ways to do that, I thought to ask if there is a simple "ip" command and such that will accomblish this without screwing up the loop detection?
BTW. I just remembered why this is tricky. If I bridge the WAN and LAN together within the router, then effectively I've created a hole in my firewall. Right now my firewall is still secure, because all the traffic going out the WAN port is PPPoE. So if someone on the internet cannot send packets directly to say my laptop, even though my laptop and DSL modem are both connected to the same HUB. If I were to just bridge WAN and LAN together, I don't know if my firewall would remain secure.