diff --git a/system/core/Config.php b/system/core/Config.php
index feea7c8..0264776 100644
--- a/system/core/Config.php
+++ b/system/core/Config.php
@@ -88,11 +88,9 @@
 		// Set the base_url automatically if none was provided
 		if (empty($this->config['base_url']))
 		{
-			// The regular expression is only a basic validation for a valid "Host" header.
-			// It's not exhaustive, only checks for valid characters.
-			if (isset($_SERVER['HTTP_HOST']) && preg_match('/^((\[[0-9a-f:]+\])|(\d{1,3}(\.\d{1,3}){3})|[a-z0-9\-\.]+)(:\d+)?$/i', $_SERVER['HTTP_HOST']))
+			if (isset($_SERVER['SERVER_ADDR']))
 			{
-				$base_url = (is_https() ? 'https' : 'http').'://'.$_SERVER['HTTP_HOST']
+				$base_url = (is_https() ? 'https' : 'http').'://'.$_SERVER['SERVER_ADDR']
 					.substr($_SERVER['SCRIPT_NAME'], 0, strpos($_SERVER['SCRIPT_NAME'], basename($_SERVER['SCRIPT_FILENAME'])));
 			}
 			else