I need a second wireless access point in my house, to deal with crappy wifi signal strength through lathe-and-plaster walls. I’m using an ASUS-RT16N running Tomato/Shibby to do this.
There’s a bunch of ways to string together wireless networks. There’s wifi repeaters (no wires), ethernet bridges, WDS, blah blah. This system is acting as a wireless access point; its whole job is to accept traffic on a wifi network and then share it to a wired ethernet.
In a nutshell, the configuration is to plug the house ethernet into one of the LAN ports on the router (not the WAN!). Then disable the WAN interface entirely in Tomato, and statically configure the router to a specific IP address on your wired network. Then set up the WAN as you’d want.
Here’s some details from Toastman. It looks a little different with the Shibby build, the LAN configuration is now hidden in this complicated bridge thing. But the idea is the same. One hint I picked up from elsewhere is to also go into the Administration thing and change the skin / color of the UI, just so you don’t get it confused with your main router.