How to stop multiple access to same web page

[Neo]

There are certain methods to do this.

1. Create a cookie and then compare it with time()
   Problem: The user can easily delete the cookie and access the page.
2. Store their IP in a database (IP + time of access) and compare their current IP and time with the database.
   Problem: The user can use proxies though this method should keep an average person away from the page.
   You may think of a more complicated solution that check whether the user is accessing through a proxy, etc...