diff --git a/system/core/Common.php b/system/core/Common.php
index cb087cb..93cd0a0 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -346,7 +346,7 @@
 	 */
 	function is_https()
 	{
-		if (isset($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) === 'on')
+		if ( ! empty($_SERVER['HTTPS']) && strtolower($_SERVER['HTTPS']) !== 'off')
 		{
 			return TRUE;
 		}
@@ -354,7 +354,7 @@
 		{
 			return TRUE;
 		}
-		elseif (isset($_SERVER['HTTP_FRONT_END_HTTPS']) && $_SERVER['HTTP_FRONT_END_HTTPS'] === 'on')
+		elseif ( ! empty($_SERVER['HTTP_FRONT_END_HTTPS']) && strtolower($_SERVER['HTTP_FRONT_END_HTTPS']) !== 'off')
 		{
 			return TRUE;
 		}