Network Working Group T. Hansen Internet-Draft AT&T Laboratories Updates: 1893,4468 April 9, 2007 (if approved) Intended status: Standards Track Expires: October 11, 2007 A Registry for Mail Enhanced Status Codes draft-hansen-4468upd-mailesc-registry-01 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 October 11, 2007. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document establishes an IANA registry for SMTP Enhanced Status Codes. Hansen Expires October 11, 2007 [Page 1] Internet-Draft Mail Enhanced Status Code Registry April 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. Normative References . . . . . . . . . . . . . . . . . . . 5 5.2. Informative References . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 Intellectual Property and Copyright Statements . . . . . . . . . . 7 Hansen Expires October 11, 2007 [Page 2] Internet-Draft Mail Enhanced Status Code Registry April 2007 1. Introduction Enhanced Status Codes for SMTP were first defined in [RFC1893], which was replaced by [RFC3463]. Since that time, various RFCs have been published and internet drafts proposed that define further status codes. However, no IANA registry was defined for the status codes and 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. This document is being discussed on the SMTP mailing list, ietf-smtp@imc.org [1]. 2. IANA Considerations o IANA is directed to create the registry Mail Enhanced Status Codes. In the terms of [RFC2434], values of Enhanced Status Codes must be registered with IANA under the IETF Consensus method. (Specifically, new assignments are made via RFCs approved by the IESG.) o The Mail Enhanced Status Codes registry will have three tables: * class sub-code, * subject sub-code, and * enumerated status codes, which include both a subject sub-code and a detail sub-code. o Each entry in the tables will include: the sub-code or enumerated status code, a definition title for the code, and a description of the code's use, similar to the entries shown in [RFC3463]. An example of an entry in the enumerated status code table would be: X.0.0 Other undefined Status 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. o The initial values for the class and subject sub-code tables is to be populated from section 2 of [RFC3463]. Specifically, these are the values for 2.XXX.XXX, 4.XXX.XXX and 5.XXX.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. o The initial values for the enumerated status code table is to be populated from 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) section 3.3.4 of [RFC3886] (X.1.9), and the definition of X.6.6 found in section 5 of [RFC4468]. o The following definitions are to be registered in the enumerated status code table. Hansen Expires October 11, 2007 [Page 3] Internet-Draft Mail Enhanced Status Code Registry April 2007 X.5.6 Authentication Exchange line is too long This enhanced status code SHOULD be returned when the server fails the AUTH command due to the client sending a response which is longer than the maximum buffer size available for the currently selected SASL mechanism. X.7.8 Trust relationship required or Authentication credentials invalid Because of conflicting definitions in different documents, this value should no longer be used. X.7.9 Authentication mechanism is too weak This response to the AUTH command indicates that the selected authentication mechanism is weaker than server policy permits for that user. The client SHOULD retry with a new authentication mechanism. X.7.10 Encryption Needed 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. X.7.11 Encryption required for requested authentication mechanism This indicates the user's passphrase or passphrase has expired and needs to be changed. Many sites have a policy which forbids a passphrase or passphrase from being used too long. These sites will set a time period after which passphrases must be changed. Some sites also pre-expire passphrases set by a system administrator, such that a user must change their passphrase prior to using their account. A client which receives this error code can treat it as a user request to change her passphrase. X.7.12 A password transition is needed This response to the AUTH command indicates that the user needs to transition to the selected authentication mechanism. This is typically done by authenticating once using the [PLAIN] authentication mechanism. The selected mechanism SHOULD then work for authentications in subsequent sessions. X.7.13 User Account Disabled 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 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. Hansen Expires October 11, 2007 [Page 4] Internet-Draft Mail Enhanced Status Code Registry April 2007 X.7.14 Trust relationship required 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. X.7.15 Authentication credentials invalid Authentication failed due to invalid or insufficient authentication credentials. This value replaces the prioruse of X.7.8 for this error condition. 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. 4. Acknowledgements Thanks go to the members of the ietf-smtp@imc.org [1] mailing list. 5. References 5.1. Normative References [RFC3463] Vaudreuil, G., "Enhanced Mail System Status Codes", RFC 3463, January 2003. [RFC3886] Allman, E., "An Extensible Message Format for Message Tracking Responses", RFC 3886, September 2004. [RFC4468] Newman, C., "Message Submission BURL Extension", RFC 4468, May 2006. 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. URIs [1] Hansen Expires October 11, 2007 [Page 5] Internet-Draft Mail Enhanced Status Code Registry April 2007 Author's Address Tony Hansen AT&T Laboratories 200 Laurel Ave. Middletown, NJ 07748 USA Email: tony+mailesc@maillennium.att.com Hansen Expires October 11, 2007 [Page 6] Internet-Draft Mail Enhanced Status Code Registry April 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). 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. 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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 Expires October 11, 2007 [Page 7]