Gets or sets the behavior of a client application's data transfer process.
Assembly: System (in System.dll)
Property ValueType: System.Boolean
false if the client application's data transfer process listens for a connection on the data port; otherwise, true if the client should initiate a connection on the data port. The default value is true.
A new value was specified for this property for a request that is already in progress.
Setting the property to true sends the "PASV" command to the server. This command requests the server to listen on a data port and to wait for a connection rather than initiate one upon receipt of a transfer command.
For a description of the behaviors that are specified using , see RFC 959, "File Transfer Protocol," Section 3.2, "Establishing Data Connections" and Section 4.1.2, "Transfer Parameter Commands," available at http://www.rfc-editor.org/.
If is set to true, the FTP server may not send the size of the file, and download progress can always be zero. If is set to false, a firewall can raise an alert and block the file download.