The Office of Information Technology has many of its servers behind a firewall to protect them and the service they provide. It is because of the firewall that if you bring a laptop computer on campus, and want to connect it to the network, that you must first log in to the network (aka authenticating). It’s also because of the firewall that you cannot automatically use Remote Desktop from home to connect to your campus computer. A firewall will block traffic based on network information such as IP address, network ports, and network protocol. It will make some decisions based on the state of the network connection.
The Microsoft Windows OS and Macintosh OS operating systems also have a built-in firewall that gives your desktop computer some added protection in addition to the University firewall.