Network Working Group T. Hansen Internet-Draft AT&T Laboratories Updates: 3463,4468,4954 J. Klensin (if approved) February 25, 2008 Intended status: Standards Track Expires: August 28, 2008 A Registry for SMTP Enhanced Mail System Status Codes draft-hansen-4468upd-mailesc-registry-04 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 28, 2008. Copyright Notice Copyright (C) The IETF Trust (2008). Abstract The specification for enhanced mail system enhanced status codes, RFC 3463, establishes a new code model and lists a collection of status codes. While it anticipated that more codes would be added over time, it did not provide an explicit mechanism for registering and tracking those codes. This document specifies an IANA registry for mail system enhanced status codes, and initializes that registry with Hansen & Klensin Expires August 28, 2008 [Page 1]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 the codes so far established in published standards-track documents, as well as other codes that have become established in the industry. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 2.1. SMTP Enhanced Status Codes Registry . . . . . . . . . . . 3 2.2. Review Process for New Values . . . . . . . . . . . . . . 4 2.3. Registration Updates . . . . . . . . . . . . . . . . . . . 5 2.4. Initial Values . . . . . . . . . . . . . . . . . . . . . . 5 3. Security Considerations . . . . . . . . . . . . . . . . . . . 8 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1. Normative References . . . . . . . . . . . . . . . . . . . 9 5.2. Informative References . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 11 Hansen & Klensin Expires August 28, 2008 [Page 2]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 1. Introduction Enhanced Status Codes for SMTP were first defined in [RFC1893], subsequently replaced by [RFC3463]. While it anticipated that more codes would be added over time (see its Section 2), it did not provide an explicit mechanism for registering and tracking those codes. Since that time, various RFCs have been published and internet drafts proposed that define further status codes. However, without an IANA registry, conflicts in definitions have begun to appear. This RFC defines such an IANA registry and was written to help prevent further conflicts from appearing in the future. It initializes the registry with the established standards-track enhanced status codes from [RFC3463], [RFC3886], [RFC4468] and [RFC4954]. In addition, several codes are added that were established by various internet drafts and have come into common use, despite the expiration of the documents themselves. NOTE: The values given in Table 1 below are incomplete. The entries denoted "Not given" should be filled in better. (RFC EDITOR NOTE: Remove this paragraph on publication.) This document is being discussed on the SMTP mailing list, ietf-smtp@imc.org. (RFC EDITOR NOTE: Remove this paragraph on publication.) 2. IANA Considerations 2.1. SMTP Enhanced Status Codes Registry IANA is directed to create the registry "SMTP Enhanced Status Codes". The Mail Enhanced Status Codes registry will have three tables: o class sub-code, o subject sub-code, and o enumerated status codes, which have an unspecified class sub-code, a specified subject sub-code, and a specified detail sub-code. Each entry in the tables will include the following. (The sub-code tables will not have the Associated Basic Status Code entries.) Code: The sub-code or enumerated status code, which will be a numeric code consisting of three components, as specified in [RFC3463]. Hansen & Klensin Expires August 28, 2008 [Page 3]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 Summary: or Sample Text: For class and subject sub-codes, this is the summary of the use for the sub- code shown in section 2 of [RFC3463]. For enumerated status codes, this is an example of a message that might be sent along with the code. Associated Basic Status Code: For enumerated status codes, the basic status code(s) of [RFC2821] with which it is usually associated. This may also have a value such as "Any" or "Not given". NOTE: This is a non-exclusive list. Description: A short description of the code. Defined: A reference to the document in which the code is defined. This reference should note whether the relevant specification is standards-track or not using "(Standards track)" or "(Not standards track)". Submitter: The identity of the submitter, usually the document author. Change Controller: The identity of the change controller for the specification. This will be "IESG" in the case of IETF-produced documents. An example of an entry in the enumerated status code table would be: Code: X.0.0 Sample Text: Other undefined Status Associated basic status code: Any Description: Other undefined status is the only undefined error code. It should be used for all errors for which only the class of the error is known. Defined: RFC 3463. (Standards track) Submitter: G. Vaudreuil Change controller: IESG. 2.2. Review Process for New Values Entries in this registry are expected to follow the "Specification Required" model ([RFC2434]) although, in practice, most entries are expected to derive from standards-track documents. Non-standards- track documents that specify codes to be registered should be readily available. The principal purpose of this registry is to avoid confusion and conflicts among different definitions or uses for the same code. Hansen & Klensin Expires August 28, 2008 [Page 4]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 The procedures from [RFC4020] may be followed to pre-allocate an Enhanced Status Code before final publication of an internet draft. 2.3. Registration Updates Standards-track registrations may be updated if the relevant standards are updated as a consequence of that action. Non- standards-track entries may be updated by the listed responsible party. Only the entry's short description or references may be modified in this way, not the code or associated text. In exceptional cases, any aspect of any registered entity may be updated at the direction of the IESG (for example, to correct a conflict). 2.4. Initial Values The initial values for the class and subject sub-code tables are to be populated from section 2 of [RFC3463]. Specifically, these are the values for 2.X.XXX, 4.X.XXX and 5.X.XXX for the class sub-code table, and the values X.0.XXX, X.1.XXX, X.2.XXX, X.3.XXX, X.4.XXX, X.5.XXX, X.6.XXX and X.7.XXX for the subject sub-code table. The code, sample text and description for each entry are to be taken from [RFC3463]. Each entry is to be designated as defined in [RFC3463], submitted by G. Vaudreuil, and change controlled by IESG. There are no associated basic status code values for the class and subject sub- code tables. The initial values for the enumerated status code table is to be populated from: 1. sections 3.1 through 3.8 of [RFC3463], (X.0.0, X.1.0 through X.1.8, X.2.0 through X.2.4, X.3.0 through X.3.5, X.4.0 through X.4.7, X.5.0 through X.5.5, X.6.0 through X.6.5, and X.7.0 through X.7.7) 2. section 3.3.4 of [RFC3886] (X.1.9), 3. X.6.6 found in section 5 of [RFC4468], 4. and X.5.6, X.7.8, X.7.9, X.7.11 and X.7.12, found in section 6 of [RFC4954]. Each entry is to be designated as defined in the corresponding RFC, submitted by the corresponding RFC author, and change controlled by the IESG. Each of the above RFCs is a standards track document. The initial values for the Associated Basic Status Code for each of the above initial enhanced status codes is given in the following table. NOTE: This table is incomplete. The entries denoted "Not given" should be filled in better. (RFC EDITOR NOTE: Remove this note on Hansen & Klensin Expires August 28, 2008 [Page 5]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 publication.) +--------+---------+--------+-------------+--------+----------------+ | Enh. | Assoc. | Enh. | Assoc. | Enh. | Assoc. Basic | | Status | Basic | Status | Basic | Status | Status Code | | Code | Status | Code | Status Code | Code | | | | Code | | | | | +--------+---------+--------+-------------+--------+----------------+ | X.0.0 | Any | X.1.0 | Not given | X.1.1 | 451, 550 | | X.1.2 | Not | X.1.3 | 501 | X.1.4 | Not given | | | given | | | | | | X.1.5 | 250 | X.1.6 | Not given | X.1.7 | Not given | | X.1.8 | 451, | X.2.0 | Not given | X.2.1 | Not given | | | 501 | | | | | | X.2.2 | 552 | X.2.3 | 552 | X.2.4 | 450, 452 | | X.3.0 | 221, | X.3.1 | 452 | X.3.2 | 453 | | | 250, | | | | | | | 421, | | | | | | | 451, | | | | | | | 550, | | | | | | | 554 | | | | | | X.3.3 | Not | X.3.4 | 552, 554 | X.3.5 | Not given | | | given | | | | | | X.4.0 | Not | X.4.1 | 451 | X.4.2 | 421 | | | given | | | | | | X.4.3 | 451, | X.4.4 | Not given | X.4.5 | 451 | | | 550 | | | | | | X.4.6 | Not | X.4.7 | Not given | X.5.0 | 220, 250, 251, | | | given | | | | 252, 253, 451, | | | | | | | 452, 454, 458, | | | | | | | 459, 501, 502, | | | | | | | 503, 554 | | X.5.1 | 430, | X.5.2 | 500, 501, | X.5.3 | 451 | | | 500, | | 502, 550, | | | | | 501, | | 555 | | | | | 503, | | | | | | | 530, | | | | | | | 550, | | | | | | | 554, | | | | | | | 555 | | | | | | X.5.4 | 451, | X.5.5 | Not given | X.5.6 | 500 | | | 501, | | | | | | | 502, | | | | | | | 503, | | | | | | | 504, | | | | | | | 550, | | | | | | | 555 | | | | | Hansen & Klensin Expires August 28, 2008 [Page 6]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 | X.6.0 | Not | X.6.1 | Not given | X.6.2 | Not given | | | given | | | | | | X.6.3 | 554 | X.6.4 | 250 | X.6.5 | Not given | | X.6.6 | 554 | X.7.0 | 220, 235, | X.7.1 | 451, 454, 502, | | | | | 450, 454, | | 503, 533, 550, | | | | | 500, 501, | | 551 | | | | | 503, 504, | | | | | | | 530, 535, | | | | | | | 550 | | | | X.7.2 | 550 | X.7.3 | Not given | X.7.4 | 504 | | X.7.5 | Not | X.7.6 | Not given | X.7.7 | Not given | | | given | | | | | | X.7.8 | 535, | X.7.9 | 534 | X.7.11 | 524, 538 | | | 554 | | | | | | X.7.12 | 422, | | | | | | | 432 | | | | | +--------+---------+--------+-------------+--------+----------------+ Table 1 The following additional definitions are to be registered in the enumerated status code table. These entries have been used in the industry without any published specification. (RFC EDITOR NOTE: change XXXX below to this document's RFC number.) Code: X.7.10 Sample Text: Encryption Needed Associated basic status code: 523 Description: This indicates that external strong privacy layer is needed in order to use the requested authentication mechanism. This is primarily intended for use with clear text authentication mechanisms. A client which receives this may activate a security layer such as TLS prior to authenticating, or attempt to use a stronger mechanism. Defined: RFC XXXX. (Standards track) Submitter: T. Hansen, J. Klensin Change controller: IESG. Code: X.7.13 Sample Text: User Account Disabled Associated basic status code: 525 Description: Sometimes a system administrator will have to disable a user's account (e.g., due to lack of payment, abuse, evidence of a break-in attempt, etc). This error code occurs after a successful authentication to a disabled account. This Hansen & Klensin Expires August 28, 2008 [Page 7]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 informs the client that the failure is permanent until the user contacts their system administrator to get the account re-enabled. It differs from a generic authentication failure where the client's best option is to present the passphrase entry dialog in case the user simply mistyped their passphrase. Defined: RFC XXXX. (Standards track) Submitter: T. Hansen, J. Klensin Change controller: IESG. Code: X.7.14 Sample Text: Trust relationship required Associated basic status code: 535, 554 Description: The submission server requires a configured trust relationship with a third-party server in order to access the message content. This value replaces the prior use of X.7.8 for this error condition. thereby updating [RFC4468]. Defined: RFC XXXX. (Standards track) Submitter: T. Hansen, J. Klensin Change controller: IESG. 3. Security Considerations As stated in [RFC1893], use of enhanced status codes may disclose additional information about how an internal mail system is implemented beyond that available through the SMTP status codes. Many proposed additions to the response code list are security related. Having these registered in one place to prevent collisions will improve their value. Security error responses can leak information to active attackers (e.g., the distinction between "user not found" and "bad password" during authentication). Documents defining security error codes should make it clear when this is the case so SMTP server software subject to such threats can provide appropriate controls to restrict exposure. 4. Acknowledgements While the need for this registry should have become clear shortly after [RFC3463] was approved, the growth of the code table through additional documents and work done as part of email internationalization and [RFC2821] updating efforts made the requirement much more clear. The comments of the participants in those efforts are gratefully acknowledged, particularly the members Hansen & Klensin Expires August 28, 2008 [Page 8]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 of the ietf-smtp@imc.org mailing list. Chris Newman and Randy Gellens provided useful comments and some text for early versions of the document. 5. References 5.1. Normative References [RFC3463] Vaudreuil, G., "Enhanced Mail System Status Codes", RFC 3463, January 2003. [RFC2821] Klensin, J., "Simple Mail Transfer Protocol", RFC 2821, April 2001. [RFC3886] Allman, E., "An Extensible Message Format for Message Tracking Responses", RFC 3886, September 2004. [RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of Standards Track Code Points", BCP 100, RFC 4020, February 2005. [RFC4468] Newman, C., "Message Submission BURL Extension", RFC 4468, May 2006. [RFC4954] Siemborski, R. and A. Melnikov, "SMTP Service Extension for Authentication", RFC 4954, July 2007. 5.2. Informative References [RFC1893] Vaudreuil, G., "Enhanced Mail System Status Codes", RFC 1893, January 1996. [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. Authors' Addresses Tony Hansen AT&T Laboratories 200 Laurel Ave. Middletown, NJ 07748 USA Email: tony+mailesc@maillennium.att.com Hansen & Klensin Expires August 28, 2008 [Page 9]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 John C Klensin 1770 Massachusetts Ave, Ste 322 Cambridge, MA 02140 USA Phone: +1 617 245 1457 Email: john+ietf@jck.com Hansen & Klensin Expires August 28, 2008 [Page 10]
Internet-Draft SMTP Enhanced Status Code Registry February 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Hansen & Klensin Expires August 28, 2008 [Page 11]
