web page redirection?

[bab1550]

i went to this website and registered for it. then i continued to webpage 1,2,3 of this site. i closed the browser. when i opened a new one, i tried to go directly to webpage 3 but instead i was diverted to the registration page. it says i can't go directly to that page without registering first.

what technique is this?

thanks in advance guys!
:)

[PeOfEo]

It is probably looking for a query string, or the value that the third page needed was not passed to it. It is not uncommon its the same prinicipal as getting taken to a login page when you try to enter a members only area of a site, basically if the server cannot find a value it is looking for that is specified in the code it redirects you. It can be done with any server side technology. I can be done client side too, but that is not secure.