# File lib/net/dns/header.rb, line 359
      def id=(val)
        if @@id_arr.include? val
          raise DuplicateIDError, "ID `#{val}' already used"
        end
        if (1..65535).include? val
          @id = val
          @@id_arr.push val
        else
          raise ArgumentError, "ID `#{val}' out of range"
        end
      end