This will attempt to give you the real IP address of a user:
// try and get the real IP address...
if (getenv('HTTP_CLIENT_IP')) {
$ip_address = getenv('HTTP_CLIENT_IP');
}elseif (getenv('HTTP_X_FORWARDED_FOR')) {
$ip_address = getenv('HTTP_X_FORWARDED_FOR');
}elseif (getenv('HTTP_X_FORWARDED')) {
$ip_address = getenv('HTTP_X_FORWARDED');
}elseif (getenv('HTTP_FORWARDED_FOR')) {
$ip_address = getenv('HTTP_FORWARDED_FOR');
}elseif (getenv('HTTP_FORWARDED')) {
$ip_address = getenv('HTTP_FORWARDED');
}else {
$ip_address = $_SERVER['REMOTE_ADDR'];
}