PuReInSaNe

I am running a PHP-based Browsergame. My actual banning system gets the ip using this function which I found to be very good. function get_real_ip() { $client_ip = (isset($_SERVER['HTTP_CLIENT_IP'])) ? $_SERVER['HTTP_CLIENT_IP'] : ''; $x_forwarded_for = (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) ? $_SERVER['HTTP_X_FORWARDED_FOR'] : ''; $remote_addr = (isset($_SERVER['REMOTE_ADDR'])) ? $_SERVER['REMOTE_ADDR'] : ''; if (!empty($client_ip)) { $ip_expl = explode('.',$client_ip); $referer = explode('.',$remote_addr); if($referer[0] != $ip_expl[0]) { $ip=array_reverse($ip_expl); $return=implode('.',$ip); } else { $return = $client_ip; } } else if (!empty($x_forwarded_for)) { if(strstr($x_forwarded_for,',')) { $ip_expl = explode(',',$x_forwarded_for); $return = end($ip_expl); } else { $return = $x_forwarded_for; } } else { $return = $remote_addr; } unset ($client_ip, $x_forwarded_for, $remote_addr, $ip_expl); return $return; } Now the problem is, that I still can't get the correct ip, a user still keeps on loggin on. So how does he do that and how to prevent him to register again and again?