The following FTP related references are useful: (Implemented or partially implemented in vsftpd): ================================================= RFC-959, original FTP spec. http://www.rfc-editor.org/rfc/rfc959.txt RFC-1123, the small FTP related section extends / clarifies RFC-959. http://www.rfc-editor.org/rfc/rfc1123.txt RFC-2228, FTP security extensions. vsftpd implements the small subset needed to support TLS / SSL connections. http://www.rfc-editor.org/rfc/rfc2228.txt RFC-2389. Proposes FEAT and OPTS commands. http://www.rfc-editor.org/rfc/rfc2389.txt RFC-2428. Essentially IPv6 support. http://www.rfc-editor.org/rfc/rfc2428.txt "Securing FTP with TLS" (draft-murray-auth-ftp-ssl-09.txt). Document that dives into the standardized behaviour of SSL / TLS connections in conjunction with RFC-2228. http://www.isaserver.org/articles/Securing_FTP_with_TLS.html "Extensions to FTP" (draft-ietf-ftpext-mlst-16.txt). Standardizes SIZE, MDTM, MLST and MLSD. Note that vsftpd has not implemented MLST and MLSD due to lack of demand from users. Perhaps the client support just isn't there. http://www.ietf.org/internet-drafts/draft-ietf-ftpext-mlst-16.txt (Not implemented in vsftpd): ============================ RFC-1579. Proposes an APSV command. No users have requested this in vsftpd; perhaps the client support just isn't there. http://www.rfc-editor.org/rfc/rfc1579.txt RFC-1639. Proposes commands LPRT and LPSV. Seems to be deprecated in favour of EPRT and EPSV in RFC-2428. http://www.rfc-editor.org/rfc/rfc1639.txt RFC-2640. Deals with internationalization and the LANG command. I'm not seeing any vsftpd users with requirements in this area. http://www.rfc-editor.org/rfc/rfc2640.txt