if ( !isset( $from_email ) ) {
         // Get the site domain and get rid of www.
         $sitename = strtolower( $_SERVER['SERVER_NAME'] );
         if ( substr( $sitename, 0, 4 ) == 'www.' ) {
                 $sitename = substr( $sitename, 4 );
         }

         $from_email = 'wordpress@' . $sitename;
 }