im buliding my site for students in my university but im facing this huge problem that i don't want anyone from outside the university to be able to register because of many reason ... so in order to prvent outsiders im gonna ask the students to register by thier university email which is This email address is being protected from spambots. You need JavaScript enabled to view it. so only students can get thier activation code ..
but my question is how can i prevent users from registering using hotmail yahoo gmail ....