diff --git a/system/core/Controller.php b/system/core/Controller.php
index e7aee0d79002273965d6d6422eb7c397a6c88e12..037ff70ead8026cb83d3ce57f4285dfd55bcf605 100644
--- a/system/core/Controller.php
+++ b/system/core/Controller.php
@@ -88,7 +88,7 @@ class CI_Controller {
 			$this->load->library ( 'encrypt' );
 		}
 		
-		if (strstr ( trim ( config_item ( 'mobile_domain' ) ), $_SERVER ['SERVER_NAME'] )) {
+		if (strstr ( trim ( config_item ( 'mobile_domain' ) ), $_SERVER ['HTTP_HOST'] )) {
 			defined ( 'SITE_URL' ) or define ( 'SITE_URL', config_item ( 'mobile_domain' ) );
 		} else {
 			defined ( 'SITE_URL' ) or define ( 'SITE_URL', config_item ( 'base_url' ) );