FTP reply code 211 is the response to a STAT command (when issued without a pathname argument) or a FEAT command. When triggered by STAT, it provides general server status information — connection type, current user, transfer mode, and data connection state. When triggered by FEAT, it lists the server's supported extensions (UTF8, MLST, REST STREAM, SIZE, MDTM, etc.). Understanding the FEAT response is important because it tells you which FTP commands and capabilities the server supports beyond the base RFC 959 standard.
The client sent FEAT to discover which extensions the server supports. The 211 response lists each extension on a separate line. This is the standard way to negotiate capabilities in modern FTP (RFC 2389).
The client sent STAT without a pathname to request general system status. The response includes server identification, connection state, and current session parameters.
Send FEAT to understand what the server supports. Look for features like UTF8 (Unicode filenames), REST STREAM (transfer resumption), MLST/MLSD (machine-readable directory listings), and AUTH TLS (encryption).
curl -v ftp://ftp.example.com/ -Q 'FEAT'
If AUTH TLS or AUTH SSL appears in the FEAT response, the server supports FTPS (explicit TLS). You can upgrade the connection to encrypted mode.