idnits 2.17.1 draft-ietf-ftpext2-typeu-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- -- The draft header indicates that this document updates RFC959, but the abstract doesn't seem to mention this, which it should. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year (Using the creation date from RFC959, updated by this document, for RFC5378 checks: 1985-10-01) -- The document seems to contain a disclaimer for pre-RFC5378 work, and may have content which was first submitted before 10 November 2008. The disclaimer is necessary when there are original authors that you have been unable to contact, or if some do not wish to grant the BCP78 rights to the IETF Trust. If you are able to get all authors (current and original) to grant those rights, you can and should remove the disclaimer; otherwise, the disclaimer is needed and you can ignore this comment. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- The document date (November 30, 2010) is 4895 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Possible downref: Non-RFC (?) normative reference: ref. 'ASCII' -- Possible downref: Non-RFC (?) normative reference: ref. 'Unicode52' Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group J. Klensin 3 Internet-Draft November 30, 2010 4 Updates: 959 (if approved) 5 Intended status: Standards Track 6 Expires: June 3, 2011 8 FTP Extension for Internationalized Text 9 draft-ietf-ftpext2-typeu-00.txt 11 Abstract 13 The original FTP protocol supported TYPE values for ASCII and EBCDIC 14 text, plus binary ("IMAGE") transmission. As the Internet becomes 15 more international, there is a growing requirement to be able to 16 transmit textual data, encoded in Unicode, in a way that is 17 independent of the coding and line representation forms of particular 18 operating systems. This memo specifies a new FTP TYPE value for 19 Unicode data. 21 Status of this Memo 23 This Internet-Draft is submitted in full conformance with the 24 provisions of BCP 78 and BCP 79. 26 Internet-Drafts are working documents of the Internet Engineering 27 Task Force (IETF). Note that other groups may also distribute 28 working documents as Internet-Drafts. The list of current Internet- 29 Drafts is at http://datatracker.ietf.org/drafts/current/. 31 Internet-Drafts are draft documents valid for a maximum of six months 32 and may be updated, replaced, or obsoleted by other documents at any 33 time. It is inappropriate to use Internet-Drafts as reference 34 material or to cite them other than as "work in progress." 36 This Internet-Draft will expire on June 3, 2011. 38 Copyright Notice 40 Copyright (c) 2010 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents 45 (http://trustee.ietf.org/license-info) in effect on the date of 46 publication of this document. Please review these documents 47 carefully, as they describe your rights and restrictions with respect 48 to this document. Code Components extracted from this document must 49 include Simplified BSD License text as described in Section 4.e of 50 the Trust Legal Provisions and are provided without warranty as 51 described in the Simplified BSD License. 53 This document may contain material from IETF Documents or IETF 54 Contributions published or made publicly available before November 55 10, 2008. The person(s) controlling the copyright in some of this 56 material may not have granted the IETF Trust the right to allow 57 modifications of such material outside the IETF Standards Process. 58 Without obtaining an adequate license from the person(s) controlling 59 the copyright in such materials, this document may not be modified 60 outside the IETF Standards Process, and derivative works of it may 61 not be created outside the IETF Standards Process, except to format 62 it for publication as an RFC or to translate it into languages other 63 than English. 65 Table of Contents 67 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 68 1.1. Context and Overview . . . . . . . . . . . . . . . . . . . 3 69 1.2. Summary of History of Internationalization of FTP . . . . . 3 70 1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 71 1.4. Discussion List . . . . . . . . . . . . . . . . . . . . . . 3 72 2. Specification . . . . . . . . . . . . . . . . . . . . . . . . . 4 73 2.1. Existing TYPEs . . . . . . . . . . . . . . . . . . . . . . 4 74 2.2. Unicode TYPE . . . . . . . . . . . . . . . . . . . . . . . 4 75 2.3. Data Structure . . . . . . . . . . . . . . . . . . . . . . 5 76 2.4. Feature Negotiation . . . . . . . . . . . . . . . . . . . . 5 77 3. Net-Unicode Format for FTP . . . . . . . . . . . . . . . . . . 5 78 4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5 79 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 80 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 81 7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 6 82 7.1. New Version and File Name: 83 draft-ietf-ftpext2-unicode-00 . . . . . . . . . . . . . . . 6 84 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 85 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 86 8.2. Informative References . . . . . . . . . . . . . . . . . . 7 87 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7 89 1. Introduction 91 1.1. Context and Overview 93 The original FTP protocol [RFC0959] supported TYPE values for ASCII 94 and EBCDIC text, plus binary ("IMAGE") transmission. The Host 95 Requirements specification [RFC1123] made other changes to FTP, but 96 did not alter the TYPE environment. 98 As the Internet becomes more international, there is a growing 99 requirement to be able to transmit textual data, encoded in Unicode 100 [Unicode52], in a way that is independent of the coding and line 101 representation forms of particular operating systems. This memo 102 specifies a new FTP TYPE value for Unicode data. 104 1.2. Summary of History of Internationalization of FTP 106 RFC 2640 [RFC2640] is described as providing internationalization of 107 FTP, but only addresses the use of FTP in internationalized (non- 108 ASCII or extended ASCII [ASCII]) file systems. Its facilities were 109 slightly enhanced in a more general extensions specification 110 [RFC3659], which builds on a more general FTP extension mechanism 111 [RFC2389]. The specification in this document addresses the transfer 112 of non-ASCII text files only, building on the TYPE command of the 113 original FTP specification [RFC0959]. 115 1.3. Terminology 117 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 118 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 119 document are to be interpreted as described in [RFC2119]. 121 This document assumes that the reader is familiar with the 122 terminology of RFC 959. Those terms, especially reply, server-FTP 123 process, user-FTP process, server-PI, user-PI, logical byte size, and 124 user, if used here, are used in the same way. It also uses the ABNF 125 of [RFC2389] and [RFC5234] in preference to the BNF of RFC 959. For 126 the convenience of contemporary readers, the terms "client" and 127 "server" are used interchangeably with the historic terms "user-FTP 128 process" and "server-FTP process". The document also assumes the 129 termology and changes in the updates to FTP specified in RFC 1123 and 130 RFC 2389. 132 1.4. Discussion List 134 [[anchor5: RFC Editor: please remove this section before 135 publication.]] 136 This proposal is being discussed in the IETF FTPEXT2 Working Group. 137 Its mailing list is at ftpext@ietf.org. 139 2. Specification 141 2.1. Existing TYPEs 143 The FTP TYPE command, described in [RFC0959] accepts four possible 144 first argument values, as described below. Note that these 145 descriptions are provided for the reader's convenience; the 146 definitions in RFC 959 remain normative. 148 A The data are expected to be in, and are transformed by the server 149 if needed to, an ASCII [ASCII] data stream conforming to the "NVT" 150 specification (See RFC 959 [RFC0959] and Appendix B of RFC 5198 151 [RFC5198] for more information). 153 E The data are expected to be in, and are transformed by the server 154 if needed to, an EBCDIC data stream as specified in RFC 959. 156 I The data are transferred in "image" form, i.e., exactly as they 157 appear in the server. Because it is the only TYPE form in which 158 true binary data can be transferred, TYPE I is often referred to 159 as "binary" or "binary transfer". 161 L The data are transmitted in logical bytes of a size specified in 162 an additional argument. See RFC 959. 164 Any of these four argument variations to TYPE except "TYPE A" (with 165 non-print format) MAY be rejected by the server-FTP process with a 166 504 response code if it does not support that type and the necessary 167 conversions. 169 2.2. Unicode TYPE 171 The client-PI MAY transmit TYPE U to the server-PI as an alternative 172 to other TYPE commands and arguments. If it does, the server MAY 173 return reply-code 504, indicating that the TYPE U feature is not 174 supported (unchanged from RFC 959) or MUST respond to any data 175 retrieval request (e.g., GET) by sending the data in a stream 176 conformant to the Net-Unicode format specified in Section 3. 177 Similarly, if the client-PI sends TYPE U and the server accepts it, 178 the client MUST send any data streams in that format while the option 179 is in effect. No second parameter is used or permitted for TYPE U. 181 2.3. Data Structure 183 The default and only permitted data structure for TYPE U is "file 184 structure". Use of the STRU command SHOULD be avoided. If is used, 185 its argument MUST be "F". 187 2.4. Feature Negotiation 189 RFC 2389 [RFC2389] specifies a feature negotiation mechanism for new 190 extensions to FTP. Since the TYPE command is a required part of the 191 base FTP specification, the client-PI is not required to issue the 192 FEAT command prior to issuing TYPE U. However, it MAY do so and 193 Server-FTP implementations that include TYPE U SHOULD support FEAT as 194 described below. If the FEAT command is transmitted from the 195 client-PI to the server-PI, and this extension and FEAT are 196 supported, the response MUST include a TYPE line that lists all TYPE 197 values supported by the server (including the required ones). For 198 example, if an FTP-server supports all of TYPEs A, E, I, and U, the 199 FEAT response line would contain each of the possible arguments 200 separated by semicolons, e.g., 202 TYPE A;E;I;U 204 This specification does not change either RFC 959 or RFC 2389. In 205 particular, no FEAT response line is required for TYPE unless this, 206 or some other, extension to TYPE is supported by the FTP-server. 208 3. Net-Unicode Format for FTP 210 This section specifies a profile of Net-Unicode [RFC5198] for use 211 with FTP TYPE U. 213 Unicode characters must be transmitted in UTF-8 as specified for Net- 214 Unicode. Because FTP is used in data transmission, the characters 215 and sequences that are discouraged in Section 2 of RFC 5198 are 216 permitted to be transported by FTP. However, line-ending sequences 217 MUST conform to the CRLF convention specified there. Consistent with 218 Paragraph 4 of that Section, strings SHOULD be normalized before 219 transmission if at all possible. 221 The implicit logical byte size for this transmission type is eight 222 bits. 224 4. Acknowledgments 226 This document draws heavily on RFC 959; appreciation is expressed to 227 its authors and to the authors of RFC 2398. The work of Mark P. 228 Peterson and Douglas J. Papenthien on other FTP extensions finally 229 motivated production of this document in 2008 after a long delay; 230 that contribution is appreciated as well. 232 5. IANA Considerations 234 When this specification is approved, an entry for "TYPE U" that 235 refers to it should be incorporated into the FTP Extensions Registry 236 established by RFC 5797 [RFC5797]. 238 6. Security Considerations 240 This specification makes no substantive change to the FTP command 241 stream but only alters the presentation of data in the data stream. 242 Consequently, it should have no negative security implications that 243 are not already present in the earlier FTP specifications described 244 in Section 1 and in the Net-Unicode specification [RFC5198]. By 245 specifying an exact canonical form for the identification and 246 transfer of Unicode strings, it may eliminate some problems that 247 might be encountered when such strings are transmitted without 248 identification or without restrictions. 250 7. Change Log 252 RFC Editor: Please remove this section 254 7.1. New Version and File Name: draft-ietf-ftpext2-unicode-00 256 This version of the document is a slight update to 257 draft-klensin-ftp-typeu-00, posted in July 2008). It includes some 258 updated references to work completed in the interim, information 259 about the FTPEXT2 WG, a new Security Considerations section (omitted 260 from the prior draft), and a few other minor corrections. 262 8. References 264 8.1. Normative References 266 [ASCII] American National Standards Institute (formerly United 267 States of America Standards Institute), "USA Code for 268 Information Interchange", ANSI X3.4-1968, 1968. 270 ANSI X3.4-1968 has been replaced by newer versions with 271 slight modifications, but the 1968 version remains 272 definitive for the Internet. 274 [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", 275 STD 9, RFC 959, October 1985. 277 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 278 Requirement Levels", BCP 14, RFC 2119, March 1997. 280 [RFC2389] Hethmon, P. and R. Elz, "Feature negotiation mechanism for 281 the File Transfer Protocol", RFC 2389, August 1998. 283 [RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for Network 284 Interchange", RFC 5198, March 2008. 286 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 287 Specifications: ABNF", STD 68, RFC 5234, January 2008. 289 [Unicode52] 290 The Unicode Consortium. The Unicode Standard, Version 291 5.2.0, defined by:, "The Unicode Standard, Version 5.2.0", 292 (Mountain View, CA: The Unicode Consortium, 2009. ISBN 293 978-1-936213-00-9)., 294 . 296 8.2. Informative References 298 [RFC1123] Braden, R., "Requirements for Internet Hosts - Application 299 and Support", STD 3, RFC 1123, October 1989. 301 [RFC2640] Curtin, B., "Internationalization of the File Transfer 302 Protocol", RFC 2640, July 1999. 304 [RFC3659] Hethmon, P., "Extensions to FTP", RFC 3659, March 2007. 306 [RFC5797] Klensin, J. and A. Hoenes, "FTP Command and Extension 307 Registry", RFC 5797, March 2010. 309 Author's Address 311 John C Klensin 312 1770 Massachusetts Ave, Ste 322 313 Cambridge, MA 02140 314 USA 316 Phone: +1 617 245 1457 317 Email: john+ietf@jck.com