FTPFTPS

FTP, or File Transfer Protocol, is a standard network protocol for transferring files between a client and a server. FTPS, also known as FTP over TLS/SSL, is an extension of FTP that adds encryption to protect control and data channels. FTPS is not SFTP.

FTPS supports two main modes: explicit and implicit. In explicit FTPS, the client connects over the standard FTP port (usually 21) and explicitly requests TLS by sending an authentication command (e.g., AUTH TLS). TLS negotiation proceeds and the session then continues encrypted. Implicit FTPS initiates TLS immediately upon connection, typically on a dedicated port (commonly 990), and the session runs encrypted from the start. Data connections are also protected when the TLS layer is used.

Security considerations: FTPS protects credentials and file data in transit, but it shares FTP’s inherent limitations, such as separate control and data connections and potential configuration complexity. It can be affected by TLS termination on proxies and by firewall rules that must allow multiple data ports, especially in passive mode. Proper certificate management is required to avoid untrusted connections.

Comparison and usage: FTPS is widely supported by many FTP servers and clients, but interoperability can be challenging due to mode (explicit vs implicit) and firewall configurations. SFTP, by contrast, uses a single secure SSH channel on a single port and is often easier to secure and firewall. Organizations choose FTPS when they require compatibility with legacy FTP workflows or specific certificate-based authentication; otherwise, SFTP or alternatives like HTTPS-based transfer are commonly recommended for modern deployments.

In summary, FTPS extends FTP with TLS/SSL encryption to secure transfers, but its use requires careful configuration to manage certificates and ports, and it should be weighed against newer secure file transfer protocols depending on the environment.