The SFTP Connector is an integral part of the Flow software suite, available as a Connector Service from version 6.14 onwards.

Its primary functions include uploading and downloading files from an SFTP server, but it's also capable of other tasks like creating remote directories and listing files and directories on the SFTP server.

The DownloadStream operation is currently limited to downloading files smaller than 100 Mb.


  • Address: Insert the designated SFTP server's address.

  • Port: Typically, the port is set to 22.

  • Server validation: Determine the server validation type. For security purposes, a public key is recommended.


  • Username and Password: Input your designated login credentials.

  • Client Private Key Path: Specify the path to the file containing the client private key. Remember, this is a path on the Flow Server when using the built-in connector and on the machine where you installed the Connector Service if you are using the Connector Service version of the connector.

  • Password to the Private Key File: Input the password associated with the private key file.

  • Keyboard-interactive: Use this setting to establish responses to potential server challenges (relevant only when using this authentication method).

Communication settings

  • SFTP Version: Define the SFTP version for use. The default setting is version 3.

  • Key Exchange Algorithms: Added in Connector Service version 2.1.0. Choose from a range of algorithms for secure key exchange. Options include various types of Diffie-Hellman (DH), RSA, Elliptic Curve Diffie-Hellman (ECDH), Curve25519 and Curve448, and GSS (Generic Security Services).

  • Auto-adjust Transfer Settings / Concurrent connections: Enable to allow the connector to automatically optimize the download and upload block size and pipeline length.

  • Pipeline Length: Define the number of concurrent pipelines permitted for the client. This is only applicable if Auto-adjust Transfer Setting / Concurrent connections are deactivated.

  • Download/Upload Block Size: Set the block size for file downloads/uploads. These options are only applicable if Auto-adjust Transfer Setting / Concurrent connections are deactivated.

  • Request Compression: If enabled, the client will demand compression explicitly.

  • Transfer Type: Select ASCII or Binary (Binary is recommended and set as default).

  • Adjust File Times: When enabled, the original date and time values of a file are preserved post-upload/download. If not enabled, the timestamp will reflect the time of the file transfer.

  • Incoming/Outgoing Traffic Limit: Set these to limit bandwidth consumption during file downloads/uploads. Zero indicates no limit.


  • Enable Log: Enable to activate logging.

  • Path to Logfile: Specify the file path where the SFTP Connector will append log output. If you're using the bundled connector, this path will be on the Flow Server machine. However, if you're utilizing the Connector Service version of the connector, the path will be on the machine where the Connector Service is installed.

  • Max Size of Logfile: Determine the maximum size of the log file (in kilobytes). Zero indicates no limit.

For a more detailed understanding of each Key Exchange Algorithm and its suitable applications, refer to the specific SFTP server's documentation or consult your network administrator.


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