Index: formatting.php
===================================================================
--- formatting.php	(revision 44523)
+++ formatting.php	(working copy)
@@ -3198,8 +3198,12 @@
 /**
  * Verifies that an email is valid.
  *
- * Does not grok i18n domains. Not RFC compliant.
+ *   rfc822 - Standard for the Format of ARPA Internet Text Messages
  *
+ *     This validates e-mail addresses against the syntax in RFC 822, 
+ *     with the exceptions that comments and whitespace folding
+ *     and dotless domain names are not supported. (php.net)
+ *
  * @since 0.71
  *
  * @param string $email      Email address to verify.
@@ -3211,77 +3215,12 @@
 		_deprecated_argument( __FUNCTION__, '3.0.0' );
 	}
 
-	// Test for the minimum length the email can be
-	if ( strlen( $email ) < 6 ) {
-		/**
-		 * Filters whether an email address is valid.
-		 *
-		 * This filter is evaluated under several different contexts, such as 'email_too_short',
-		 * 'email_no_at', 'local_invalid_chars', 'domain_period_sequence', 'domain_period_limits',
-		 * 'domain_no_periods', 'sub_hyphen_limits', 'sub_invalid_chars', or no specific context.
-		 *
-		 * @since 2.8.0
-		 *
-		 * @param bool   $is_email Whether the email address has passed the is_email() checks. Default false.
-		 * @param string $email    The email address being checked.
-		 * @param string $context  Context under which the email was tested.
-		 */
-		return apply_filters( 'is_email', false, $email, 'email_too_short' );
-	}
+	$is_email = filter_var( $email, FILTER_VALIDATE_EMAIL );
 
-	// Test for an @ character after the first position
-	if ( strpos( $email, '@', 1 ) === false ) {
-		/** This filter is documented in wp-includes/formatting.php */
-		return apply_filters( 'is_email', false, $email, 'email_no_at' );
+	if ( !$is_email ) {
+		return apply_filters( 'is_email', false, $email, 'RFC822' );
 	}
 
-	// Split out the local and domain parts
-	list( $local, $domain ) = explode( '@', $email, 2 );
-
-	// LOCAL PART
-	// Test for invalid characters
-	if ( ! preg_match( '/^[a-zA-Z0-9!#$%&\'*+\/=?^_`{|}~\.-]+$/', $local ) ) {
-		/** This filter is documented in wp-includes/formatting.php */
-		return apply_filters( 'is_email', false, $email, 'local_invalid_chars' );
-	}
-
-	// DOMAIN PART
-	// Test for sequences of periods
-	if ( preg_match( '/\.{2,}/', $domain ) ) {
-		/** This filter is documented in wp-includes/formatting.php */
-		return apply_filters( 'is_email', false, $email, 'domain_period_sequence' );
-	}
-
-	// Test for leading and trailing periods and whitespace
-	if ( trim( $domain, " \t\n\r\0\x0B." ) !== $domain ) {
-		/** This filter is documented in wp-includes/formatting.php */
-		return apply_filters( 'is_email', false, $email, 'domain_period_limits' );
-	}
-
-	// Split the domain into subs
-	$subs = explode( '.', $domain );
-
-	// Assume the domain will have at least two subs
-	if ( 2 > count( $subs ) ) {
-		/** This filter is documented in wp-includes/formatting.php */
-		return apply_filters( 'is_email', false, $email, 'domain_no_periods' );
-	}
-
-	// Loop through each sub
-	foreach ( $subs as $sub ) {
-		// Test for leading and trailing hyphens and whitespace
-		if ( trim( $sub, " \t\n\r\0\x0B-" ) !== $sub ) {
-			/** This filter is documented in wp-includes/formatting.php */
-			return apply_filters( 'is_email', false, $email, 'sub_hyphen_limits' );
-		}
-
-		// Test for invalid characters
-		if ( ! preg_match( '/^[a-z0-9-]+$/i', $sub ) ) {
-			/** This filter is documented in wp-includes/formatting.php */
-			return apply_filters( 'is_email', false, $email, 'sub_invalid_chars' );
-		}
-	}
-
 	// Congratulations your email made it!
 	/** This filter is documented in wp-includes/formatting.php */
 	return apply_filters( 'is_email', $email, $email, null );