Authentication (AUTH) - KB Article #1475Related Articles --
The AUTH command is used to initialize a secure connection to the connected FTP server. Included with the AUTH command is a case-insensitive parameter defining the security mechinism the client is requesting to use to secure the session. Sample security mechanisms used by popular FTP clients are SSL and TLS. The AUTH command should be followed by a USER command to authenticate access to the server after establishing a secure channel. The AUTH command is not used to secure the connection if secure connections are implicitly required by the server (usually done by allowing connections on port 990).