Using FTP passive mode, after the client opens the command channel (port 21 ) to the FTP server and requests passive mode, what will be the next step ?
A.
The FTP server sends back an acknowledgment (ACK) to the client
B.
The FTP server opens the data channel to the client using the port number indicated by the client
C.
The FTP client opens the data channel to the FTP server on Port 21
D.
The FTP server allocates a port to use for the data channel and transmit that port number to the client
E.
The FTP client opens the data channel to the FTP server on Port 20