FTP Commands and Extensions

Created

2010-01-07

Last Updated

2024-04-22

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Registry included below

• FTP Commands and Extensions

FTP Commands and Extensions

Expert(s)

John Klensin

Reference

[RFC5797]

Note

Note: An IESG Standards Action is allowed to direct IANA to change the
Conformance Requirements listed for any entry. 

The following commands are part of the base FTP specification
[RFC959] and are listed in the registry with the immutable pseudo
FEAT code "base".

Mandatory commands:

ABOR, ACCT, ALLO, APPE, CWD, DELE, HELP, LIST, MODE, NLST, NOOP,
PASS, PASV, PORT, QUIT, REIN, REST, RETR, RNFR, RNTO, SITE, STAT,
STOR, STRU, TYPE, USER

Optional commands:

CDUP, MKD, PWD, RMD, SMNT, STOU, SYST

Note: STD 3 [RFC1123] clarified and updated the status and
implementation requirements of these standard FTP commands, and it
contains important complementary information for the following
commands:

LIST, NLST, PASV, REST, SITE, STOU

The following commands were specified as experimental in an extension
to an early version of the FTP specification [RFC775] but later
deprecated by [RFC1123], because Standard FTP [RFC959]
specifies their standard successors.  They are listed in the registry
with the immutable pseudo FEAT code "hist".

XCUP, XCWD, XMKD, XPWD, XRMD

Implementation note:  Deployed FTP clients still make use of the
deprecated commands and most FTP servers support them as aliases
for the standard commands.

The following commands were specified as part of the "FOOBAR" IPng
effort in [RFC1545] and, later, [RFC1639] and are
now obsolete.  They are listed in the registry with the immutable
pseudo FEAT code "hist".

LPRT, LPSV

Legend for the registry:

    o  cmd (Command Name)

        Amended versions of commands are tagged with a trailing "+"

    o  FEAT Code

        Keyword returned in FEAT response line for this command/extension:

          - actual FEAT codes are given in upper case
          - placeholders (pseudo FEAT codes) are shown in lower case
          - "-N/A-" indicates a feature not related to one particular command

        See the "Extension name" clause in Section 2.2 of
        [RFC5797] for details.

    o  description

        Brief description of command / extension

    o  type (Command Type)

        Type or "kind" of command, based on Section 4.1 of [RFC959]:

          'a'  ... access control
          'p'  ... parameter setting
          's'  ... service execution

        Combinations like 'p/s' are possible.

    o  conf (Conformance Requirements)

        Expectation for support in modern FTP implementations:

          'm'  ... mandatory to implement
          'o'  ... optional
          'h'  ... historic
  

Available Formats

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Footnotes

While an IETF Standards Action would be required to make the FEAT
mechanism [RFC2389] mandatory, implementation of that extension
mechanism is clearly required in conjunction with any extension or
feature that depends on it.

FEAT String for [RFC4217]: AUTH TLS
FEAT String for [RFC2773]: AUTH KEA-SKIPJACK

FEAT String: REST STREAM

FEAT String: TYPE {semicolon-separated list of supported types}