File Transfer Protocol
RFC 959
| Document | Type |
RFC - Internet Standard
(October 1985; Errata)
Obsoletes RFC 765
Also known as STD 9
|
|
|---|---|---|---|
| Last updated | 2013-03-02 | ||
| Stream | Legacy | ||
| Formats | plain text pdf html bibtex | ||
| Stream | Legacy state | (None) | |
| Consensus Boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | RFC 959 (Internet Standard) | |
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
Network Working Group J. Postel
Request for Comments: 959 J. Reynolds
ISI
Obsoletes RFC: 765 (IEN 149) October 1985
FILE TRANSFER PROTOCOL (FTP)
Status of this Memo
This memo is the official specification of the File Transfer
Protocol (FTP). Distribution of this memo is unlimited.
The following new optional commands are included in this edition of
the specification:
CDUP (Change to Parent Directory), SMNT (Structure Mount), STOU
(Store Unique), RMD (Remove Directory), MKD (Make Directory), PWD
(Print Directory), and SYST (System).
Note that this specification is compatible with the previous edition.
1. INTRODUCTION
The objectives of FTP are 1) to promote sharing of files (computer
programs and/or data), 2) to encourage indirect or implicit (via
programs) use of remote computers, 3) to shield a user from
variations in file storage systems among hosts, and 4) to transfer
data reliably and efficiently. FTP, though usable directly by a user
at a terminal, is designed mainly for use by programs.
The attempt in this specification is to satisfy the diverse needs of
users of maxi-hosts, mini-hosts, personal workstations, and TACs,
with a simple, and easily implemented protocol design.
This paper assumes knowledge of the Transmission Control Protocol
(TCP) [2] and the Telnet Protocol [3]. These documents are contained
in the ARPA-Internet protocol handbook [1].
2. OVERVIEW
In this section, the history, the terminology, and the FTP model are
discussed. The terms defined in this section are only those that
have special significance in FTP. Some of the terminology is very
specific to the FTP model; some readers may wish to turn to the
section on the FTP model while reviewing the terminology.
Postel & Reynolds [Page 1]
RFC 959 October 1985
File Transfer Protocol
2.1. HISTORY
FTP has had a long evolution over the years. Appendix III is a
chronological compilation of Request for Comments documents
relating to FTP. These include the first proposed file transfer
mechanisms in 1971 that were developed for implementation on hosts
at M.I.T. (RFC 114), plus comments and discussion in RFC 141.
RFC 172 provided a user-level oriented protocol for file transfer
between host computers (including terminal IMPs). A revision of
this as RFC 265, restated FTP for additional review, while RFC 281
suggested further changes. The use of a "Set Data Type"
transaction was proposed in RFC 294 in January 1982.
RFC 354 obsoleted RFCs 264 and 265. The File Transfer Protocol
was now defined as a protocol for file transfer between HOSTs on
the ARPANET, with the primary function of FTP defined as
transfering files efficiently and reliably among hosts and
allowing the convenient use of remote file storage capabilities.
RFC 385 further commented on errors, emphasis points, and
additions to the protocol, while RFC 414 provided a status report
on the working server and user FTPs. RFC 430, issued in 1973,
(among other RFCs too numerous to mention) presented further
comments on FTP. Finally, an "official" FTP document was
published as RFC 454.
By July 1973, considerable changes from the last versions of FTP
were made, but the general structure remained the same. RFC 542
was published as a new "official" specification to reflect these
changes. However, many implementations based on the older
specification were not updated.
In 1974, RFCs 607 and 614 continued comments on FTP. RFC 624
proposed further design changes and minor modifications. In 1975,
RFC 686 entitled, "Leaving Well Enough Alone", discussed the
differences between all of the early and later versions of FTP.
RFC 691 presented a minor revision of RFC 686, regarding the
subject of print files.
Motivated by the transition from the NCP to the TCP as the
underlying protocol, a phoenix was born out of all of the above
efforts in RFC 765 as the specification of FTP for use on TCP.
This current edition of the FTP specification is intended to
correct some minor documentation errors, to improve the
explanation of some protocol features, and to add some new
optional commands.
Postel & Reynolds [Page 2]
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