nameserver2 => {
            "validator"    => fun_ref(Yast::IP.method(:Check), "boolean (string)"),
            "setter"       => fun_ref(method(:SetNameserver2), "void (any)"),
            "fail_message" => Ops.add(
              Ops.add(Ops.add(_("Invalid IP. "), Yast::IP.Valid4), "\n"),