Index: includes/common.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/common.inc,v
retrieving revision 1.686
diff -u -r1.686 common.inc
--- includes/common.inc	14 Sep 2007 20:08:59 -0000	1.686
+++ includes/common.inc	16 Oct 2007 22:34:05 -0000
@@ -772,6 +772,8 @@
  * Verify the syntax of the given e-mail address.
  *
  * Empty e-mail addresses are allowed. See RFC 2822 for details.
+ * This version is based on Cal Henderson's.
+ * See http://www.iamcal.com/publish/articles/php/parsing_email/
  *
  * @param $mail
  *   A string containing an e-mail address.
@@ -779,12 +781,34 @@
  *   TRUE if the address is in a valid format.
  */
 function valid_email_address($mail) {
-  $user = '[a-zA-Z0-9_\-\.\+\^!#\$%&*+\/\=\?\`\|\{\}~\']+';
-  $domain = '(?:(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.?)+';
-  $ipv4 = '[0-9]{1,3}(\.[0-9]{1,3}){3}';
-  $ipv6 = '[0-9a-fA-F]{1,4}(\:[0-9a-fA-F]{1,4}){7}';
-
-  return preg_match("/^$user@($domain|(\[($ipv4|$ipv6)\]))$/", $mail);
+  
+  // Get the strict variable
+  $strict = variable_get('valid_email_address_strict', FALSE);
+
+  // Build our regex
+  $qtext = '[^\\x0d\\x22\\x5c\\x80-\\xff]';
+  $dtext = '[^\\x0d\\x5b-\\x5d\\x80-\\xff]';
+  $atom = '[^\\x00-\\x20\\x22\\x28\\x29\\x2c\\x2e\\x3a-\\x3c\\x3e\\x40\\x5b-\\x5d\\x7f-\\xff]+';
+  $quoted_pair = '\\x5c[\\x00-\\x7f]';
+  $domain_literal = "\\x5b($dtext|$quoted_pair)*\\x5d";
+  $quoted_string = "\\x22($qtext|$quoted_pair)*\\x22";
+  $domain_ref = $atom;
+  $sub_domain = "($domain_ref|$domain_literal)";
+  $word = "($atom|$quoted_string)";
+  $domain = "$sub_domain(\\x2e$sub_domain)*";
+  $local_part = "$word(\\x2e$word)*";
+
+  // Validate in strict accordance with RFC 2822
+  if ($strict) {
+    $strict_addr_spec = "$local_part\\x40$domain";
+    return preg_match("!^$strict_addr_spec$!", $mail);
+  }
+  
+  // Validate so that we require a ".*" at the end of the email
+  else {
+    $rl_addr_spec = "($local_part\\x40(?:[-a-z0-9]+\.)+[a-z]{2,})";
+    return preg_match("!^$rl_addr_spec$!", $mail);
+  }
 }
 
 /**