Hooking up a hard drive to the Ethernet port of my Airport Extreme base station.

What do you mean by a “Network hard drive?” Are you talking about an external NAS drive with its own built in Ethernet port? If so, you should be able to connect it to one of the Ethernet ports on th back of the airport.

Sorry, I wasn’t very specific. When I said “network hard drive”, I meant something along these lines: http://www.lacie.com/us/products/range.htm?id=1000 Basically, an external hard drive with an ethernet port on the back (among other things).

the answer is yes:

you can attach a NAS drive to the ethernet port on an airport base station, and it will be visible to computers connected via wifi.