Definition
FTP transfers in clear text. Username, password and content all travel unprotected, and the protocol has no place in production today. FTPS is the same protocol with TLSCryptographic protocol that secures data in transit between two systems - the successor to SSL, and the reason data cannot be intercepted or altered along the way. wrapped around it: same commands, encrypted transport. It uses two separate connections, one for commands and one for data, which is why it is awkward through firewalls and NAT. SFTP, despite the name, is not FTP at all but a file transfer protocol running over SSH - one connection, one port, its own command set. It is often chosen precisely because it is easy to allow through a firewall. The short version: FTPS is FTP with security added, SFTP is something else that inherited the name. In the energy sector all three turn up in integrations with older systems, and it is worth knowing which one you actually have.