I'm currently in the university halls, and therefore connected to the university network. All internet traffic (in and out) goes through a HTTP/NAT firewall router, therefore direct connects to my computer are ruled out (overlooking tunneling, and any similar technologies).

The problem is that i'd like to host a ftp server to allow my friend to download a large file from my computer. I've descovered, downloaded and played with the ftp server i plan to use.

Another service the university always provides is user (e.g student/staff) webspace. This webspace allows for use of HTML, CSS etc etc and PHP. My question is, would in theory i be able to create a webpage using the university webspace (and PHP) that detected any connections coming from the outside world, which then connected to my pc (inside the network) and set up a session to send the file to my friend.