Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 18537)
+++ wp-includes/formatting.php	(working copy)
@@ -1493,59 +1493,10 @@
 	if ( ! empty( $deprecated ) )
 		_deprecated_argument( __FUNCTION__, '3.0' );
 
-	// Test for the minimum length the email can be
-	if ( strlen( $email ) < 3 ) {
-		return apply_filters( 'is_email', false, $email, 'email_too_short' );
-	}
-
-	// Test for an @ character after the first position
-	if ( strpos( $email, '@', 1 ) === false ) {
-		return apply_filters( 'is_email', false, $email, 'email_no_at' );
-	}
-
-	// 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 ) ) {
-		return apply_filters( 'is_email', false, $email, 'local_invalid_chars' );
-	}
-
-	// DOMAIN PART
-	// Test for sequences of periods
-	if ( preg_match( '/\.{2,}/', $domain ) ) {
-		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 ) {
-		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 ) ) {
-		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 ) {
-			return apply_filters( 'is_email', false, $email, 'sub_hyphen_limits' );
-		}
-
-		// Test for invalid characters
-		if ( !preg_match('/^[a-z0-9-]+$/i', $sub ) ) {
-			return apply_filters( 'is_email', false, $email, 'sub_invalid_chars' );
-		}
-	}
-
-	// Congratulations your email made it!
-	return apply_filters( 'is_email', $email, $email, null );
+	if (!filter_var($email, FILTER_VALIDATE_EMAIL) )
+		return apply_filters( 'is_email', false, $email, 'invalid_email' );
+	else
+		return apply_filters( 'is_email', $email, $email, null );
 }
 
 /**
@@ -1711,77 +1662,15 @@
  * @return string Filtered email address.
  */
 function sanitize_email( $email ) {
-	// Test for the minimum length the email can be
-	if ( strlen( $email ) < 3 ) {
-		return apply_filters( 'sanitize_email', '', $email, 'email_too_short' );
-	}
-
-	// Test for an @ character after the first position
-	if ( strpos( $email, '@', 1 ) === false ) {
-		return apply_filters( 'sanitize_email', '', $email, 'email_no_at' );
-	}
-
-	// Split out the local and domain parts
-	list( $local, $domain ) = explode( '@', $email, 2 );
-
-	// LOCAL PART
-	// Test for invalid characters
-	$local = preg_replace( '/[^a-zA-Z0-9!#$%&\'*+\/=?^_`{|}~\.-]/', '', $local );
-	if ( '' === $local ) {
-		return apply_filters( 'sanitize_email', '', $email, 'local_invalid_chars' );
-	}
-
-	// DOMAIN PART
-	// Test for sequences of periods
-	$domain = preg_replace( '/\.{2,}/', '', $domain );
-	if ( '' === $domain ) {
-		return apply_filters( 'sanitize_email', '', $email, 'domain_period_sequence' );
-	}
-
-	// Test for leading and trailing periods and whitespace
-	$domain = trim( $domain, " \t\n\r\0\x0B." );
-	if ( '' === $domain ) {
-		return apply_filters( 'sanitize_email', '', $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 ) ) {
-		return apply_filters( 'sanitize_email', '', $email, 'domain_no_periods' );
-	}
-
-	// Create an array that will contain valid subs
-	$new_subs = array();
-
-	// Loop through each sub
-	foreach ( $subs as $sub ) {
-		// Test for leading and trailing hyphens
-		$sub = trim( $sub, " \t\n\r\0\x0B-" );
-
-		// Test for invalid characters
-		$sub = preg_replace( '/[^a-z0-9-]+/i', '', $sub );
-
-		// If there's anything left, add it to the valid subs
-		if ( '' !== $sub ) {
-			$new_subs[] = $sub;
-		}
-	}
-
-	// If there aren't 2 or more valid subs
-	if ( 2 > count( $new_subs ) ) {
-		return apply_filters( 'sanitize_email', '', $email, 'domain_no_valid_subs' );
-	}
-
-	// Join valid subs into the new domain
-	$domain = join( '.', $new_subs );
-
-	// Put the email back together
-	$email = $local . '@' . $domain;
-
-	// Congratulations your email made it!
-	return apply_filters( 'sanitize_email', $email, $email, null );
+	
+	// Sanitize first
+	$email = filter_var($email, FILTER_SANITIZE_EMAIL);
+	
+	// Check it for validity
+	if ( FALSE === filter_var($email, FILTER_VALIDATE_EMAIL) )
+		return apply_filters( 'sanitize_email', '', $email, 'invalid_email' );
+	else
+		return apply_filters( 'sanitize_email', $email, $email, null );
 }
 
 /**