You can only use some restricted access services of the university or the state and university library if you are on campus, so that the computer you are using has an address from the area allocated to the university.
If you want to access these services from home or on the go with an account from the Center for Networks, you have to install a so-called VPN client software (AnyConnect or OpenConnect) on your computer and use the VPN Client establish a connection to the campus. This means that you are “virtually” on campus and can use the usual services.
Only current employees and students of the university are allowed to use the VPN service. For licensing reasons, use by alumni, for example, is excluded.