diff --git a/index.php b/index.php
index 4729324..d48e388 100644
--- a/index.php
+++ b/index.php
@@ -47,7 +47,7 @@ define('WEB_PATH', substr($_SERVER["REQUEST_URI"], 0, 1+strrpos($_SERVER["REQUES
 // Force cookie path (but do not change lifetime)
 $cookie=session_get_cookie_params();
 $cookiedir = ''; if(dirname($_SERVER['SCRIPT_NAME'])!='/') $cookiedir=dirname($_SERVER["SCRIPT_NAME"]).'/';
-session_set_cookie_params($cookie['lifetime'],$cookiedir,$_SERVER['HTTP_HOST']); // Set default cookie expiration and path.
+session_set_cookie_params($cookie['lifetime'],$cookiedir,$_SERVER['SERVER_NAME']); // Set default cookie expiration and path.
 
 // Set session parameters on server side.
 define('INACTIVITY_TIMEOUT',3600); // (in seconds). If the user does not access any page within this time, his/her session is considered expired.
@@ -406,14 +406,14 @@ if (isset($_POST['login']))
             $_SESSION['expires_on']=time()+$_SESSION['longlastingsession'];  // Set session expiration on server-side.
 
             $cookiedir = ''; if(dirname($_SERVER['SCRIPT_NAME'])!='/') $cookiedir=dirname($_SERVER["SCRIPT_NAME"]).'/';
-            session_set_cookie_params($_SESSION['longlastingsession'],$cookiedir,$_SERVER['HTTP_HOST']); // Set session cookie expiration on client side
+            session_set_cookie_params($_SESSION['longlastingsession'],$cookiedir,$_SERVER['SERVER_NAME']); // Set session cookie expiration on client side
             // Note: Never forget the trailing slash on the cookie path!
             session_regenerate_id(true);  // Send cookie with new expiration date to browser.
         }
         else // Standard session expiration (=when browser closes)
         {
             $cookiedir = ''; if(dirname($_SERVER['SCRIPT_NAME'])!='/') $cookiedir=dirname($_SERVER["SCRIPT_NAME"]).'/';
-            session_set_cookie_params(0,$cookiedir,$_SERVER['HTTP_HOST']); // 0 means "When browser closes"
+            session_set_cookie_params(0,$cookiedir,$_SERVER['SERVER_NAME']); // 0 means "When browser closes"
             session_regenerate_id(true);
         }
         // Optional redirect after login:
@@ -445,7 +445,7 @@ function serverUrl()
 {
     $https = (!empty($_SERVER['HTTPS']) && (strtolower($_SERVER['HTTPS'])=='on')) || $_SERVER["SERVER_PORT"]=='443'; // HTTPS detection.
     $serverport = ($_SERVER["SERVER_PORT"]=='80' || ($https && $_SERVER["SERVER_PORT"]=='443') ? '' : ':'.$_SERVER["SERVER_PORT"]);
-    return 'http'.($https?'s':'').'://'.$_SERVER['HTTP_HOST'].$serverport;
+    return 'http'.($https?'s':'').'://'.$_SERVER['SERVER_NAME'].$serverport;
 }
 
 // Returns the absolute URL of current script, without the query.