Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.752
diff -u -p -r1.752 common.inc
--- includes/common.inc	16 Jan 2008 10:37:30 -0000	1.752
+++ includes/common.inc	25 Jan 2008 16:24:59 -0000
@@ -815,7 +815,8 @@ function t($string, $args = array(), $la
  */
 function valid_email_address($mail) {
   $user = '[a-zA-Z0-9_\-\.\+\^!#\$%&*+\/\=\?\`\|\{\}~\']+';
-  $domain = '(?:(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.?)+';
+  $subdomain = '(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])';
+  $domain = "(?:$subdomain\.?)*$subdomain";
   $ipv4 = '[0-9]{1,3}(\.[0-9]{1,3}){3}';
   $ipv6 = '[0-9a-fA-F]{1,4}(\:[0-9a-fA-F]{1,4}){7}';