I have a mbp running leopard and I run into this issue when I try to connect to my university network that it says the ip is in use when using airport. It doesn't let me refresh it or anything, and restarting doesn't work. It can't even connect when physically plugged into the wall either... Other computers seem to be able to connect fine, so I can't figure out what is going on. Thanks a lot for the help! EDIT: It just fixed itself, but I didn't really do anything so I'm not sure if it was my computer or the network messing up...Anyway, thanks for the help!