RFC 2389 (rfc2389) - Page 2 of 9
Feature negotiation mechanism for the File Transfer Protocol
Alternative Format: Original Text Document
RFC 2389 Feature negotiation mechanism August 1998
Table of Contents
Abstract ................................................ 1
1 Introduction ............................................ 2
2 Document Conventions .................................... 2
2.1 Basic Tokens ............................................ 3
2.2 Server Replies .......................................... 3
3 Knowledge of Extra Capabilities - the FEAT Command ...... 3
3.1 Feature (FEAT) Command Syntax ........................... 4
3.2 FEAT Command Responses .................................. 4
3.3 Rationale for FEAT ...................................... 6
4 The OPTS Command ........................................ 6
5 Security Considerations ................................. 7
6 References .............................................. 8
Acknowledgements ........................................ 8
Editors' Addresses ...................................... 8
Full Copyright Statement ................................ 9
1. Introduction
This document amends the File Transfer Protocol (FTP) [1]. Two new
commands are added: "FEAT" and "OPTS".
These commands allow a client to discover which optional commands a
server supports, and how they are supported, and to select among
various options that any FTP command may support.
2. Document Conventions
This document makes use of the document conventions defined in BCP14
[2]. That provides the interpretation of some capitalized words like
MUST, SHOULD, etc.
Terms defined in [1] will be used here as defined there. These
include ASCII, reply, server-FTP process, user-FTP process, server-
PI, user-PI, and user.
Syntax required is defined using the Augmented BNF defined in [3].
Some general ABNF definitions are required throughout the document,
those will be defined here. At first reading, it may be wise to
simply recall that these definitions exist here, and skip to the next
section.
Hethmon & Elz Standards Track