There is this popular website I go to called 4chan. It contains several boards where people post images. On one of the boards, if I try to upload anything I get an error "proxy detected on port :80". This occurs on people within the university network that I'm in. It works fine if I connect to dialup. Anyway, I e-mailed the site administrator and he said "Close port 80. Your uni is undoubtedly running httpd or a proxy." I ran a port scanner internet thing and it listed my port 80 as open. How do I close port 80?