function get_client_ip() {

    if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))

        $ip = getenv("HTTP_CLIENT_IP");

    else if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"),

"unknown"))

        $ip = getenv("HTTP_X_FORWARDED_FOR");

    else if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))

        $ip = getenv("REMOTE_ADDR");

    else if (isset ($_SERVER['REMOTE_ADDR']) &&

$_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))

        $ip = $_SERVER['REMOTE_ADDR'];

    else

        $ip = "unknown";

    return ($ip);

}

echo get_client_ip();