How to turn on debug messages in log file in FileZilla FTP Client? I want to know more about how FileZilla communicating with my FTP server.

You can turn on debug messages in log files in FileZilla FTP Client by following these steps:

1. Go to "Edit > Settings > Debug". You see the "Debug settings" showing up.

2. Select "4 - Debug" in the "Debug information in message log" dropdown list.

3. Click "OK" to save changes.

4. Connect to your FTP server and perform file transfer in the same way as you normally do.

5. Open the log file (for example: C:\temp\filezilla.log) in a text editor. You should see additional debug messages as shown below:

... Status: Resolving address of ftp.somebody.com
... Status: Connecting to xx.xx.xx.xx:21...
... Status: Connection established, waiting for welcome message...
... Trace: CFtpControlSocket::OnReceive()
... Response: 220 Welcome to my FTP site!
... Trace: CFtpControlSocket::SendNextCommand()
... Command: AUTH TLS
... Trace: CFtpControlSocket::OnReceive()
... Response: 500 Protocol not supported.
... Trace: CFtpControlSocket::SendNextCommand()
... Command: AUTH SSL
... Trace: CFtpControlSocket::OnReceive()
... Response: 500 Protocol not supported.
... Status: Insecure server, it does not support FTP over TLS.
... Trace: CFtpControlSocket::SendNextCommand()
... Command: USER username
... Trace: CFtpControlSocket::OnReceive()
... Response: 331 Password required for username.
... Trace: CFtpControlSocket::SendNextCommand()
... Command: PASS ********
... Trace: CFtpControlSocket::OnReceive()
... Response: 230 Login OK. Proceed.
... Status: Server does not support non-ASCII characters.
... Status: Logged in
... Trace: CFtpControlSocket::ResetOperation(0)
... Trace: CControlSocket::ResetOperation(0)
... Trace: CFileZillaEnginePrivate::ResetOperation(0)
... Trace: Measured latency of 70 ms

... Status: Retrieving directory listing...
... Trace: CFtpControlSocket::SendNextCommand()
... Trace: CFtpControlSocket::ChangeDirSend()
... Command: PWD
... Trace: CFtpControlSocket::OnReceive()
... Response: 257 "/" is current folder.
... Trace: CFtpControlSocket::ResetOperation(0)
... Trace: CControlSocket::ResetOperation(0)
... Trace: CFtpControlSocket::ParseSubcommandResult(0)
... Trace: CFtpControlSocket::ListSubcommandResult()
... Trace:   state = 1
... Trace: CFtpControlSocket::SendNextCommand()
... Trace: CFtpControlSocket::TransferSend()
... Trace:   state = 1
... Command: TYPE I
... Trace: CFtpControlSocket::OnReceive()
... Response: 200 Type set to I.
... Trace: CFtpControlSocket::TransferParseResponse()
... Trace:   code = 2
... Trace:   state = 1
... Trace: CFtpControlSocket::SendNextCommand()
... Trace: CFtpControlSocket::TransferSend()
... Trace:   state = 2
... Command: PASV
... Trace: CFtpControlSocket::OnReceive()
... Response: 227 Entering Passive Mode (xx,xx,xx,xx,109,96).
... Trace: CFtpControlSocket::TransferParseResponse()
... Trace:   code = 2
... Trace:   state = 2
... Trace: CFtpControlSocket::SendNextCommand()
... Trace: CFtpControlSocket::TransferSend()
... Trace:   state = 4
... Trace: Binding data connection source IP to control connection source IP 192.168.1.7
... Command: MLSD
... Trace: CTransferSocket::OnConnect
... Trace: CFtpControlSocket::OnReceive()
... Response: 150 Opening BINARY mode data connection for MLSD /.
... Trace: CFtpControlSocket::TransferParseResponse()
... Trace:   code = 1
... Trace:   state = 4
... Trace: CFtpControlSocket::SendNextCommand()
... Trace: CFtpControlSocket::TransferSend()
... Trace:   state = 5
... Trace: CTransferSocket::OnReceive(), m_transferMode=0
... Trace: CTransferSocket::TransferEnd(1)
... Trace: CFtpControlSocket::TransferEnd()
... Trace: CFtpControlSocket::OnReceive()
... Response: 226 Transfer complete. 684 bytes transferred. 684 bps.
... Trace: CFtpControlSocket::TransferParseResponse()
... Trace:   code = 2
... Trace:   state = 7
... Trace: CFtpControlSocket::ResetOperation(0)
... Trace: CControlSocket::ResetOperation(0)
... Trace: CFtpControlSocket::ParseSubcommandResult(0)
... Trace: CFtpControlSocket::ListSubcommandResult()
... Trace:   state = 3
... Trace: CFtpControlSocket::ResetOperation(0)
... Trace: CControlSocket::ResetOperation(0)
... Status: Directory listing of "/" successful
...

⇒ SFTP Log File Entries in FileZilla FTP Client

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