The following commands and options MUST be supported by every server-FTP and user-FTP, except in cases where the underlying file system or operating system does not allow or support a particular command.
Type: ASCII Non-print, IMAGE, LOCAL 8 Mode: Stream Structure: File, Record* Commands: USER, PASS, ACCT, PORT, PASV, TYPE, MODE, STRU, RETR, STOR, APPE, RNFR, RNTO, DELE, CWD, CDUP, RMD, MKD, PWD, LIST, NLST, SYST, STAT, HELP, NOOP, QUIT. * Record structure is REQUIRED only for hosts whose file systems support record structure.
Vendors are encouraged to implement a larger subset of the protocol. For example, there are important robustness features in the protocol (e.g., Restart, ABOR, block mode) that would be an aid to some Internet users but are not widely implemented.
A host that does not have record structures in its file system may still accept files with STRU R, recording the byte stream literally.