How to implement 511 response from the server?

Question

PHP

if($enable==0)
{
# сюда присылает неавторизированных пользователей файерволл
    if ($_SERVER['SERVER_NAME'] != "$servername.$domain_name")
    {
  
  header("location:http://$servername.$domain_name/index.php?add=" .
            urldecode($_SERVER['SERVER_NAME'] . $_SERVER['REQUEST_URI']));
        exit;
    }

I know that the authorization header looks like this

header('HTTP/1.1 511 Network Authentication Required', TRUE, 511);

please tell me how
to implement it correctly so that unauthorized users are immediately automatically sent to captive portal detection?

Answer 1

511 Network Authentication Required - this response is not sent by the server to which the request was intended, but by an intermediary server - for example, the provider's server - if the client must first log in to the network, for example, enter a password for a paid Internet access point. It is assumed that the body of the response will return a web authorization form or a redirect to it. Introduced in RFC 6585 Draft
try similar to 301

<?php 
 header("HTTP/1.1 511 Network Authentication Required "); 
 header("Location: http://www.host.ru"); 
 exit(); 
 ?>