sftp2.exe is a Windows port of the Unix sftp2 tool.
sftp2 (Secure File Transfer Protocol 2) is an FTP-like client that can be used for file transfer over the network. sftp2 uses Secure Shell version 2 protocol in data connections, so the file transport is secure.
However, it should be noted that sftp2 is not designed to be a drop-in replacement for an FTP client. It is an application that implements secure file transfer functionality and has most features that common FTP applications have.
In order to connect using sftp2, you need to make sure that sshd2 is running on the remote host computer you are connecting to.
sftp2.exe launches ssh2.exe as a transport. Therefore the configuration and authentication features of ssh2.exe can be used in sftp2.exe as well.