The ChannelMode property property array is used to change
the security mode for either the command or data channel. The
property array index specifies the channel that should be changed,
and may be one of the following values:
| Value |
Description |
| ftpChannelCommand |
Change or return information for the command channel. This
is the communication channel used to send commands to the
server and receive command result and status information from
the server. |
| ftpChannelData |
Change information for the data channel. This is the
communication channel used to send or receive data during a
file transfer. |
The mode value specifies the new security mode for the
specified channel. It may be one of the following values:
| Value |
Description |
| ftpChannelClear |
Data sent and received on this channel should not be
encrypted. |
| ftpChannelSecure |
Data sent and received on this channel should be encrypted.
Specifying this option requires that a secure connection has
already been established with the server. |
The ChannelMode property array is used to change the
default mode for the specified channel, and is typically used to
control whether or not data is encrypted during a file transfer. If a
standard, non-secure connection has been established with the server,
an error will be returned if you specify the ftpChannelSecure
mode for either channel.
If you have established a secure connection and then specify the
ftpChannelClear mode for the command channel, the client will
send the CCC command to the server to indicate that commands should
no longer be encrypted. If the server does not support this command,
an error will be returned and the channel mode will remain unchanged.
Once the command channel has been changed to clear mode, it cannot be
changed back to secure mode. You must disconnect and re-connect to
the server if you want to resume sending commands over an encrypted
channel.
Changing the mode for the data channel requires that the server
support the PROT command. If this command is not supported by the
server, an exception will be thrown which must be handled by the
application. You can only set a channel to secure mode if the
Secure property is also set to True.
It is important to note that this property array should only be
used after a connection has been established with the server. If you
attempt to read the property or change a value prior to calling the
Connect method, an exception will be thrown.