Students needing a dataset for a class should avoid any that are marked "restricted." Although restricted data is available under certain conditions, the paperwork cannot be processed quickly enough to meet class deadlines. Restricted data is fine for researchers working on dissertations, books, etc.
ICPSR detects the IP address of your computer to confirm that it falls within range of an affiliated institution. If you are off-campus the first time you attempt to set up an ICPSR account for downloading, you will be out of range and it will be necessary to install a free software from DoIT called Virtual Private Networking (VPN.) On the other hand, if you get your account initially set up using an on-campus machine, your logon info will authenticate you whether you are on campus or off.