How to create port on public IP address? (Port Forwarding)?

I go to a university and I use their internet. I'm trying to set up a minecraft server my friends and I can play on, but the address 25565 is already being used and the command prompt for the server keeps failing. I can't just type in my IP address because it just brings me to an error page. I don't know what to do here. You can't. To do port forwarding, you need access to the university router, and obviously they aren't going to let you do that, nor would they allow you to run a server that can be accessed via the internet.

You can possibly run a local server for friends at the university to connect to. However, the IT department may actually kill that too.

Your only real option is a hosted service offsite.