Turns off the sending of the PORT FTP command to the remote FTP
    host.
    By default, FTP sends a PORT protocol command when establishing a
    connection for each data transfer. If the PORT command fails, FTP
    uses the default data port (20).
    Disable the PORT command when communicating with certain FTP
    implementations that ignore PORT commands.
    DCL Format
      DISABLE PORT_COMMAND
    UNIX Format
      sendport