check useragent

<?php
    $config_useragent = "myUserAgent";
    $config_password = "myPassWord";

    $userAgent = $_SERVER['HTTP_USER_AGENT'];
    if (!((strpos(strtolower($userAgent), strtolower($config_useragent)) != false) && (strtolower($_POST["pw"]) == strtolower($config_password))))
    {
        die("404");
        exit;
    }

    /*
        Errthing else here
    */
?>