18.104.22.168.1 Receiving an NT_TRANSACT_IOCTL Request
The NT_TRANSACT_IOCTL extensions listed in section 22.214.171.124.1 are not directly passed to the underlying object store. Instead, processing is as specified in the following sections.
If the IsFsctl field is set to zero, the server SHOULD<135> fail the request with STATUS_NOT_SUPPORTED.
When the server receives an undefined FSCTL or IOCTL operation request that does not meet the private FSCTL requirements of [MS-FSCC]2.3, the server MUST NOT pass the request to the underlying object store and MUST fail the request with STATUS_NOT_SUPPORTED.