> Ah, okay.  This seems simple enough.  My question regarding this,
> though, is: What if I don't know what they have their local IP set to?
> Does it need to match their IP, or is there a more "generic" one I
> can use, such as the 127.0.0.1 address that vruz mentioned, that will
> work no matter what for the local host?

yes, 127.0.0.1 is your safest bet.

It won't be useful if you need to access the app from other machines
in the local network though.

If you need the app to be accessible from other machines in the local
network you may have to detect the available local addresses
(generally something in the 192.168.xxx.xxx range)
but that detection is probably system-dependent.

cheers,
                         vruz