SSH (Secure Shell) is a standard protocol that provides encrypted data transmission over a network. To use SSH you need SSH client that can communicate with SSH servers. The protocol has two key modifications: SSH-1 and SSH-2. SSH enables secure file transfer (via SFTP or SCP), tunneling and port forwarding. The Secure Shell protocol is commonly used for encrypting the otherwise insecure FTP connections.
FTP over SSH
FTP over SSH is a method of securing your FTP connection. It differs from the SFTP protocol, which is an extension to SHH that creates constantly encrypted connection using SFTP servers. FTP over SSH takes the unencrypted FTP traffic but sends it via an encrypted SSH tunnel (sends the FTP protocol data via the SSH protocol).
FTP over SSH or SFTP
FTP over SSH is one of the ways to protect your data when you use FTP to transfer files. However, establishing FTP connection over SSH is a particularly complicated and difficult task that requires advanced technical skills. Unless it is really necessary, you’d better use SFTP, which also utilizes SSH, so it is just as secure as FTP over SSH (even more as it encrypts the passwords and the data transmitted) and it is supported by most modern FTP clients.