The use of some of the University’s online services is limited to the university network for licence-related reasons. These services include the databases and electronic journals offered by the library. To use these services on a computer outside the university network, you are required to establish a secure connection between your home computer and the university server.
The most common technology for establishing such a connection is VPN (Wikipedia). To use a VPN connection, you need a valid university username. Check the installation instructions for different operating systems.