Question

in my project i need to allow rating system for users only once.
i have a table in my database, where i store all ip addresses, and i check, if the user’s ip is not in database, i allow rating.

But now i met a problem.

There are providers, that generate random ip addresses every time user restart computer.

So when i call $ip=$_SERVER['REMOTE_ADDR'];, every time it returns different result from the same computer.

I also tried something like

if (!empty($_SERVER['HTTP_CLIENT_IP']))   //check ip from share internet
    {
        $ip=$_SERVER['HTTP_CLIENT_IP'];
    }
    elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR']))   //to check ip is pass from proxy
    {
        $ip=$_SERVER['HTTP_X_FORWARDED_FOR'];
    }
    else
    {
        $ip=$_SERVER['REMOTE_ADDR'];
    }

But it doesn’t help.

How can i solve this problem?

Thanks much

Answer 1

You have to accept that some users will have changing IP’s.

If your voting system is important, consider adding registration, email verification along with IP checks to filter out primitive cheats.

Again though it’s always quite easy to cheat on those sorts of systems (web proxies for example)