It seems like all these routers are adding too many variables to the situation. While I can't just use the landlord's router (he'd have wires all over his house!) I can, at least, take the old airport extreme out of the equation and try from there. There is also a wifi card in the Tower that isn't b...

Jason, thanks for the help, but i don't think my current networking background is strong enough to understand everything you've posted. It seems that your LAN is 10.0.1.0/24 (or 10.0.1.0 mask 255.255.255.0) and that your landlords LAN is 10.8.0.0/24 (or 10.8.0.0 mask 255.255.255.0) actually, the lan...

Using the Network Troubleshooter, I failed step 5 - Router is reachable?. Here's a paste to help troubleshoot: http://amahi.pastebin.com/6hE3aHcs Little background on the network... Modem -> landlord's router (with his own LAN) -> OLD airport extreme ( with my LAN and wireless b/g) -> NEW Dual-band ...