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I'm trying to establish a connection with a FTP server by using FTPS. The server is configured to request a TLS communication for the authentification only, that means the datas have to be send in clear. So, to do that, I tried the ClearControlChannel method. It seems to work but when I try to send a file to the server, my application freezes. So, I then try to use the SendCommand method : PBSZ 0, PROT C, CCC. When I try to send a file, I have now this return :

ChilkatLog: PutFile: DllDate: Jan 21 2015 ChilkatVersion: UnlockPrefix: SEPAMEFTP Username: METEO-ETUDES:EMI Architecture: Little Endian; 32-bit Language: ActiveX VerboseLogging: 0 LocalFilename: C:/FichiersXML/GRmaintenance.xml RemoteFilename: /home/ftpuser/upload/GRmaintenance.xml ProgressMonitoring: enabled: yes heartbeatMs: 0 sendBufferSize: 65536 --ProgressMonitoring IdleTimeoutMs: 60000 ReceiveTimeoutMs: 60000 ConnectTimeoutSeconds: 60 uploadFromLocalFile: localFileSize: 13560 uploadFromDataSource: initialGreeting: 220-Ubuntu 14.04.1 LTS n l 220 FTP Server ready. restartNext: 0 modeZ: 0 binaryMode: 1 pbsz_protp: sendCommand: prepControlChannel: processAlert: TlsAlert: level: warning descrip: close notify --TlsAlert --processAlert --prepControlChannel sendingCommand: PBSZ 0 --sendCommand readCommandResponse: Already received close-notify. Failed to receive more bytes. Failed to read FTP control channel reply. --readCommandResponse --pbsz_protp --uploadFromDataSource Failed. --uploadFromLocalFile TotalTime: Elapsed time: 0 millisec Failed. --PutFile --ChilkatLog

What can be wrong ?


asked Jul 02 '15 at 12:02

deletme's gravatar image


The ClearControlChannel method is to revert the control/command channel back to an unencrypted connection. That's not what you want.

What you instead want is for the control/command connection to be encrypted (which it is), but for the data connections to be unencrypted. This new build includes a new DataProtection property:


See the online documentation for it, which I've just now updated.


DataProtection: Controls the data protection level for the data connections. Possible values are "control", "clear", or "private".

  • "control" is the default, and the data connections will be the same as for the control connection. If the control connection is SSL/TLS, then the data connections are also SSL/TLS. If the control connection is unencrypted, then the data connections will also be unencrypted.
  • "clear" means that the data connections will always be unencrypted.
  • "private" means that the data connections will always be encrypted.

Let me know if you have trouble..


answered Jul 02 '15 at 13:33

chilkat's gravatar image

chilkat ♦♦


Thanks, it seems clear. I'm going to try rigth now.


answered Jul 03 '15 at 03:28

deletme's gravatar image


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Asked: Jul 02 '15 at 12:02

Seen: 1,879 times

Last updated: Jul 03 '15 at 03:28

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