The SSH File Transfer Protocol (SFTP) Server provides secure file transfer functionality over any reliable data stream. It is the standard file transfer protocol for use with the SSH2 protocol and the SFTP server runs at the application layer as a subsystem of SSH2. Using public-key cryptography, SSH2 creates the secure channel over which SFTP runs. More than a simple file transfer protocol, SFTP would be better described as a file management system with commands to create files, copy files, delete files, create directories, change directories, list directories etc.
The SFTP Server is integrated with our SSH product as an optional add-on.