return 405 or 301 when not using POST

index.php

 <?php
 
 if ($_SERVER['REQUEST_METHOD'] == 'GET') {
+    http_response_code(301);
     header('Location: admin.php');
     die();
 }
-if ($_SERVER['REQUEST_METHOD'] != 'POST') die("unknown method");
+if ($_SERVER['REQUEST_METHOD'] != 'POST') {
+    http_response_code(405);
+    die("unknown method");
+}
 
 define('MAX_REPORT_BY_ORG', 100000);
 define('MAX_REPORT_BY_NET', 100000);