AUTH (Authorization)

FTP server subcommand

The AUTH FTP server subcommand defines the authentication/security mechanism that is used for the current FTP session. The syntax of this subcommand is:

AUTH [ TLS-C | TLS-P | TLS | SSL ]

Parameter values:

TLS-C Utilize the Transport Layer Security (TLS) protocol as the security mechanism. The security settings for the data connection use the RFC2228 defaults; that is, there is no implicit protection of the data connection.
TLS-P Utilize the TLS protocol as the security mechanism. Also, implicitly protect the data connection (which is equivalent to the command sequence AUTH TLC-C, PBSZ 0, PROT P)
TLS Synonym for TLS-C.
SSL Synonym for TLS-P.
Note: The TLS protocol is compatible with the Secure Sockets Layer (SSL) protocol.
Related reference
File Transfer Protocol server syntax conventions