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diff --git a/doc/rfc/rfc5530.txt b/doc/rfc/rfc5530.txt new file mode 100644 index 0000000..946fbb5 --- /dev/null +++ b/doc/rfc/rfc5530.txt @@ -0,0 +1,507 @@ + + + + + + +Network Working Group A. Gulbrandsen +Request for Comments: 5530 Oryx Mail Systems GmbH +Category: Standards Track May 2009 + + + IMAP Response Codes + +Status of This Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (c) 2009 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents in effect on the date of + publication of this document (http://trustee.ietf.org/license-info). + Please review these documents carefully, as they describe your rights + and restrictions with respect to this document. + +Abstract + + IMAP responses consist of a response type (OK, NO, BAD), an optional + machine-readable response code, and a human-readable text. + + This document collects and documents a variety of machine-readable + response codes, for better interoperation and error reporting. + + + + + + + + + + + + + + + + + + +Gulbrandsen Standards Track [Page 1] + +RFC 5530 IMAP Response Codes May 2009 + + +1. Introduction + + Section 7.1 of [RFC3501] defines a number of response codes that can + help tell an IMAP client why a command failed. However, experience + has shown that more codes are useful. For example, it is useful for + a client to know that an authentication attempt failed because of a + server problem as opposed to a password problem. + + Currently, many IMAP servers use English-language, human-readable + text to describe these errors, and a few IMAP clients attempt to + translate this text into the user's language. + + This document names a variety of errors as response codes. It is + based on errors that have been checked and reported on in some IMAP + server implementations, and on the needs of some IMAP clients. + + This document doesn't require any servers to test for these errors or + any clients to test for these names. It only names errors for better + reporting and handling. + +2. Conventions Used in This Document + + Formal syntax is defined by [RFC5234] as modified by [RFC3501]. + + Example lines prefaced by "C:" are sent by the client and ones + prefaced by "S:" by the server. "[...]" means elision. + +3. Response Codes + + This section defines all the new response codes. Each definition is + followed by one or more examples. + + UNAVAILABLE + Temporary failure because a subsystem is down. For example, an + IMAP server that uses a Lightweight Directory Access Protocol + (LDAP) or Radius server for authentication might use this + response code when the LDAP/Radius server is down. + + C: a LOGIN "fred" "foo" + S: a NO [UNAVAILABLE] User's backend down for maintenance + + AUTHENTICATIONFAILED + Authentication failed for some reason on which the server is + unwilling to elaborate. Typically, this includes "unknown + user" and "bad password". + + + + + + +Gulbrandsen Standards Track [Page 2] + +RFC 5530 IMAP Response Codes May 2009 + + + This is the same as not sending any response code, except that + when a client sees AUTHENTICATIONFAILED, it knows that the + problem wasn't, e.g., UNAVAILABLE, so there's no point in + trying the same login/password again later. + + C: b LOGIN "fred" "foo" + S: b NO [AUTHENTICATIONFAILED] Authentication failed + + AUTHORIZATIONFAILED + Authentication succeeded in using the authentication identity, + but the server cannot or will not allow the authentication + identity to act as the requested authorization identity. This + is only applicable when the authentication and authorization + identities are different. + + C: c1 AUTHENTICATE PLAIN + [...] + S: c1 NO [AUTHORIZATIONFAILED] No such authorization-ID + + C: c2 AUTHENTICATE PLAIN + [...] + S: c2 NO [AUTHORIZATIONFAILED] Authenticator is not an admin + + + EXPIRED + Either authentication succeeded or the server no longer had the + necessary data; either way, access is no longer permitted using + that passphrase. The client or user should get a new + passphrase. + + C: d login "fred" "foo" + S: d NO [EXPIRED] That password isn't valid any more + + PRIVACYREQUIRED + The operation is not permitted due to a lack of privacy. If + Transport Layer Security (TLS) is not in use, the client could + try STARTTLS (see Section 6.2.1 of [RFC3501]) and then repeat + the operation. + + C: d login "fred" "foo" + S: d NO [PRIVACYREQUIRED] Connection offers no privacy + + C: d select inbox + S: d NO [PRIVACYREQUIRED] Connection offers no privacy + + + + + + + +Gulbrandsen Standards Track [Page 3] + +RFC 5530 IMAP Response Codes May 2009 + + + CONTACTADMIN + The user should contact the system administrator or support + desk. + + C: e login "fred" "foo" + S: e OK [CONTACTADMIN] + + NOPERM + The access control system (e.g., Access Control List (ACL), see + [RFC4314]) does not permit this user to carry out an operation, + such as selecting or creating a mailbox. + + C: f select "/archive/projects/experiment-iv" + S: f NO [NOPERM] Access denied + + INUSE + An operation has not been carried out because it involves + sawing off a branch someone else is sitting on. Someone else + may be holding an exclusive lock needed for this operation, or + the operation may involve deleting a resource someone else is + using, typically a mailbox. + + The operation may succeed if the client tries again later. + + C: g delete "/archive/projects/experiment-iv" + S: g NO [INUSE] Mailbox in use + + EXPUNGEISSUED + Someone else has issued an EXPUNGE for the same mailbox. The + client may want to issue NOOP soon. [RFC2180] discusses this + subject in depth. + + C: h search from fred@example.com + S: * SEARCH 1 2 3 5 8 13 21 42 + S: h OK [EXPUNGEISSUED] Search completed + + CORRUPTION + The server discovered that some relevant data (e.g., the + mailbox) are corrupt. This response code does not include any + information about what's corrupt, but the server can write that + to its logfiles. + + C: i select "/archive/projects/experiment-iv" + S: i NO [CORRUPTION] Cannot open mailbox + + + + + + + +Gulbrandsen Standards Track [Page 4] + +RFC 5530 IMAP Response Codes May 2009 + + + SERVERBUG + The server encountered a bug in itself or violated one of its + own invariants. + + C: j select "/archive/projects/experiment-iv" + S: j NO [SERVERBUG] This should not happen + + CLIENTBUG + The server has detected a client bug. This can accompany all + of OK, NO, and BAD, depending on what the client bug is. + + C: k1 select "/archive/projects/experiment-iv" + [...] + S: k1 OK [READ-ONLY] Done + C: k2 status "/archive/projects/experiment-iv" (messages) + [...] + S: k2 OK [CLIENTBUG] Done + + CANNOT + The operation violates some invariant of the server and can + never succeed. + + C: l create "///////" + S: l NO [CANNOT] Adjacent slashes are not supported + + LIMIT + The operation ran up against an implementation limit of some + kind, such as the number of flags on a single message or the + number of flags used in a mailbox. + + C: m STORE 42 FLAGS f1 f2 f3 f4 f5 ... f250 + S: m NO [LIMIT] At most 32 flags in one mailbox supported + + OVERQUOTA + The user would be over quota after the operation. (The user + may or may not be over quota already.) + + Note that if the server sends OVERQUOTA but doesn't support the + IMAP QUOTA extension defined by [RFC2087], then there is a + quota, but the client cannot find out what the quota is. + + C: n1 uid copy 1:* oldmail + S: n1 NO [OVERQUOTA] Sorry + + C: n2 uid copy 1:* oldmail + S: n2 OK [OVERQUOTA] You are now over your soft quota + + + + + +Gulbrandsen Standards Track [Page 5] + +RFC 5530 IMAP Response Codes May 2009 + + + ALREADYEXISTS + The operation attempts to create something that already exists, + such as when the CREATE or RENAME directories attempt to create + a mailbox and there is already one of that name. + + C: o RENAME this that + S: o NO [ALREADYEXISTS] Mailbox "that" already exists + + NONEXISTENT + The operation attempts to delete something that does not exist. + Similar to ALREADYEXISTS. + + C: p RENAME this that + S: p NO [NONEXISTENT] No such mailbox + +4. Formal Syntax + + The following syntax specification uses the Augmented Backus-Naur + Form (ABNF) notation as specified in [RFC5234]. [RFC3501] defines + the non-terminal "resp-text-code". + + Except as noted otherwise, all alphabetic characters are case- + insensitive. The use of upper or lowercase characters to define + token strings is for editorial clarity only. + + resp-text-code =/ "UNAVAILABLE" / "AUTHENTICATIONFAILED" / + "AUTHORIZATIONFAILED" / "EXPIRED" / + "PRIVACYREQUIRED" / "CONTACTADMIN" / "NOPERM" / + "INUSE" / "EXPUNGEISSUED" / "CORRUPTION" / + "SERVERBUG" / "CLIENTBUG" / "CANNOT" / + "LIMIT" / "OVERQUOTA" / "ALREADYEXISTS" / + "NONEXISTENT" + +5. Security Considerations + + Revealing information about a passphrase to unauthenticated IMAP + clients causes bad karma. + + Response codes are easier to parse than human-readable text. This + can amplify the consequences of an information leak. For example, + selecting a mailbox can fail because the mailbox doesn't exist, + because the user doesn't have the "l" right (right to know the + mailbox exists) or "r" right (right to read the mailbox). If the + server sent different responses in the first two cases in the past, + only malevolent clients would discover it. With response codes it's + possible, perhaps probable, that benevolent clients will forward the + + + + + +Gulbrandsen Standards Track [Page 6] + +RFC 5530 IMAP Response Codes May 2009 + + + leaked information to the user. Server authors are encouraged to be + particularly careful with the NOPERM and authentication-related + responses. + +6. IANA Considerations + + The IANA has created the IMAP Response Codes registry. The registry + has been populated with the following codes: + + NEWNAME RFC 2060 (obsolete) + REFERRAL RFC 2221 + ALERT RFC 3501 + BADCHARSET RFC 3501 + PARSE RFC 3501 + PERMANENTFLAGS RFC 3501 + READ-ONLY RFC 3501 + READ-WRITE RFC 3501 + TRYCREATE RFC 3501 + UIDNEXT RFC 3501 + UIDVALIDITY RFC 3501 + UNSEEN RFC 3501 + UNKNOWN-CTE RFC 3516 + UIDNOTSTICKY RFC 4315 + APPENDUID RFC 4315 + COPYUID RFC 4315 + URLMECH RFC 4467 + TOOBIG RFC 4469 + BADURL RFC 4469 + HIGHESTMODSEQ RFC 4551 + NOMODSEQ RFC 4551 + MODIFIED RFC 4551 + COMPRESSIONACTIVE RFC 4978 + CLOSED RFC 5162 + NOTSAVED RFC 5182 + BADCOMPARATOR RFC 5255 + ANNOTATE RFC 5257 + ANNOTATIONS RFC 5257 + TEMPFAIL RFC 5259 + MAXCONVERTMESSAGES RFC 5259 + MAXCONVERTPARTS RFC 5259 + NOUPDATE RFC 5267 + METADATA RFC 5464 + NOTIFICATIONOVERFLOW RFC 5465 + BADEVENT RFC 5465 + UNDEFINED-FILTER RFC 5466 + UNAVAILABLE RFC 5530 + AUTHENTICATIONFAILED RFC 5530 + AUTHORIZATIONFAILED RFC 5530 + + + +Gulbrandsen Standards Track [Page 7] + +RFC 5530 IMAP Response Codes May 2009 + + + EXPIRED RFC 5530 + PRIVACYREQUIRED RFC 5530 + CONTACTADMIN RFC 5530 + NOPERM RFC 5530 + INUSE RFC 5530 + EXPUNGEISSUED RFC 5530 + CORRUPTION RFC 5530 + SERVERBUG RFC 5530 + CLIENTBUG RFC 5530 + CANNOT RFC 5530 + LIMIT RFC 5530 + OVERQUOTA RFC 5530 + ALREADYEXISTS RFC 5530 + NONEXISTENT RFC 5530 + + The new registry can be extended by sending a registration request to + IANA. IANA will forward this request to a Designated Expert, + appointed by the responsible IESG Area Director, CCing it to the IMAP + Extensions mailing list at <ietf-imapext@imc.org> (or a successor + designated by the Area Director). After either allowing 30 days for + community input on the IMAP Extensions mailing list or a successful + IETF Last Call, the expert will determine the appropriateness of the + registration request and either approve or disapprove the request by + sending a notice of the decision to the requestor, CCing the IMAP + Extensions mailing list and IANA. A denial notice must be justified + by an explanation, and, in cases where it is possible, concrete + suggestions on how the request can be modified so as to become + acceptable should be provided. + + For each response code, the registry contains a list of relevant RFCs + that describe (or extend) the response code and an optional response + code status description, such as "obsolete" or "reserved to prevent + collision with deployed software". (Note that in the latter case, + the RFC number can be missing.) Presence of the response code status + description means that the corresponding response code is NOT + RECOMMENDED for widespread use. + + The intention is that any future allocation will be accompanied by a + published RFC (including direct submissions to the RFC Editor). But + in order to allow for the allocation of values prior to the RFC being + approved for publication, the Designated Expert can approve + allocations once it seems clear that an RFC will be published, for + example, before requesting IETF LC for the document. + + The Designated Expert can also approve registrations for response + codes used in deployed software when no RFC exists. Such + registrations must be marked as "reserved to prevent collision with + deployed software". + + + +Gulbrandsen Standards Track [Page 8] + +RFC 5530 IMAP Response Codes May 2009 + + + Response code registrations may not be deleted; response codes that + are no longer believed appropriate for use (for example, if there is + a problem with the syntax of said response code or if the + specification describing it was moved to Historic) should be marked + "obsolete" in the registry, clearly marking the lists published by + IANA. + +7. Acknowledgements + + Peter Coates, Mark Crispin, Philip Guenther, Alexey Melnikov, Ken + Murchison, Chris Newman, Timo Sirainen, Philip Van Hoof, Dale + Wiggins, and Sarah Wilkin helped with this document. + +8. References + +8.1. Normative References + + [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION + 4rev1", RFC 3501, March 2003. + + [RFC5234] Crocker, D., Ed., and P. Overell, "Augmented BNF for + Syntax Specifications: ABNF", STD 68, RFC 5234, January + 2008. + +9. Informative References + + [RFC2087] Myers, J., "IMAP4 QUOTA extension", RFC 2087, January + 1997. + + [RFC2180] Gahrns, M., "IMAP4 Multi-Accessed Mailbox Practice", RFC + 2180, July 1997. + + [RFC4314] Melnikov, A., "IMAP4 Access Control List (ACL) Extension", + RFC 4314, December 2005. + +Author's Address + + Arnt Gulbrandsen + Oryx Mail Systems GmbH + Schweppermannstr. 8 + D-81671 Muenchen + Germany + + Fax: +49 89 4502 9758 + EMail: arnt@oryx.com + + + + + + +Gulbrandsen Standards Track [Page 9] + |