Request for Comments: 7017
IMAP Access to IETF Email List Archives
The IETF makes heavy use of email lists to conduct its work. This often involves accessing the archived history of those email lists. Participants would like to have the ability to browse and search those archives using standard IMAP clients. This memo captures the requirements for providing a service that would allow such browsing and searching, and it is intended as input to a later activity for the design and development of such a service.
Status of This Memo
This document is not an Internet Standards Track specification; it is published for informational purposes.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are a candidate for any level of Internet Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7017.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Requirements for IMAP Access to Archived IETF Lists . . . . . 2 3. Internationalized Address Considerations . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. Informative References . . . . . . . . . . . . . . . . . . . 4
The IETF makes heavy use of email lists to conduct its work. This often involves accessing the archived history of those email lists. Requirements for improved web-based browsing and searching of these archives are captured in [RFC6778]. Participants would like to have the ability to browse and search those archives using standard IMAP clients. This memo captures the requirements for providing a service that would allow such browsing and searching, and it is intended as input to a later activity for the design and development of such a service.
2. Requirements for IMAP Access to Archived IETF Lists
Many participants would prefer to access the list archives using IMAP [RFC3501]. Providing this access while meeting the following requirements will likely require an IMAP server with specialized capabilities.
- The system should expose the archive using an IMAP interface, with each list represented as a mailbox.
- This interface must work with standard IMAP clients.
- The interface should allow users that have provided credentials to each have their own read/unread marks for messages. Allowing other annotation is desirable. The implementation should consider taking advantage of the IMAP extensions for ANNOTATE [RFC5257] and METADATA [RFC5464].
- It must be possible for administrators to set per-user storage quotas, limiting the space a user can consume with annotations.
- The interface must not allow users to modify the underlying message or metadata other than the read/unread marks and annotations described above. Specifically, users must not be able to delete or insert messages, or move them between mailboxes in the archive. (Clients will, of course, be able to make local copies of messages from the archive.)
- The interface must have server-side searching enabled and should scale to support multiple simultaneous extensive searches. The server should provide the enhanced search capabilities described in [RFC6778]. The implementation should consider taking advantage of the extensions defined for IMAP SORT and THREAD [RFC5256], multimailbox search [RFC6237], and fuzzy search [RFC6203].
- When the system requires credentials, it must use the datatracker's authentication system.
- While the vast majority of archived lists have an open access policy, some archived lists have restricted archives. The system must make it possible to limit access to a restricted archive based on login credentials. - The system must allow access to open archives with or without providing credentials. Specifically, the system will allow anonymous access using the Simple Authentication and Security Layer (SASL) ANONYMOUS mechanism [RFC4505] or a LOGIN command with a special username (such as "anonymous") determined by the administrator.
3. Internationalized Address Considerations
4. Security Considerations
Allowing IMAP as an interface for browsing and searching the archives of IETF email lists does not affect the security of the Internet in any significant fashion.
Searching can be input/output (I/O) and CPU intensive. Clients that make local copies of all messages in a mailbox can also present an I/O burden, particularly when synchronizing for the first time. The implementors of this interface should consider the potential for maliciously crafted searches attempting to consume a damaging amount of resources. The implementors should consider the potential for denial-of-service attacks through making many connections to the interface. The implementors should consider ways to rate limit I/O due to making local copies of messages.
Storing read/unread marks and other annotations requires potentially unbounded storage space. The implementors of this interface should consider the potential for maliciously crafted annotations attempting to consume a damaging amount of storage space. The implementors should consider making it easy to alert the administrator when a user begins consuming exceptional amounts of space.
This text was derived directly from an early version of the document that became [RFC6778], which incorporated text suggestions from Alexey Melnikov, Pete Resnick, and S. Moonesamy. Barry Leiba suggested several references to IMAP extensions for an implementation to consider. Reviews were provided by Martin Duerst, Carl Wallace, Wassim Haddad, and Juergen Schoenwaelder.
6. Informative References
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1", RFC 3501, March 2003. [RFC4505] Zeilenga, K., "Anonymous Simple Authentication and Security Layer (SASL) Mechanism", RFC 4505, June 2006. [RFC5256] Crispin, M. and K. Murchison, "Internet Message Access Protocol - SORT and THREAD Extensions", RFC 5256, June 2008. [RFC5257] Daboo, C. and R. Gellens, "Internet Message Access Protocol - ANNOTATE Extension", RFC 5257, June 2008. [RFC5464] Daboo, C., "The IMAP METADATA Extension", RFC 5464, February 2009. [RFC6203] Sirainen, T., "IMAP4 Extension for Fuzzy Search", RFC 6203, March 2011. [RFC6237] Leiba, B. and A. Melnikov, "IMAP4 Multimailbox SEARCH Extension", RFC 6237, May 2011. [RFC6531] Yao, J. and W. Mao, "SMTP Extension for Internationalized Email", RFC 6531, February 2012. [RFC6532] Yang, A., Steele, S., and N. Freed, "Internationalized Email Headers", RFC 6532, February 2012. [RFC6778] Sparks, R., "Requirements for Archiving IETF Email Lists and for Providing Web-Based Browsing and Searching", RFC 6778, October 2012. [RFC6855] Resnick, P., Newman, C., and S. Shen, "IMAP Support for UTF-8", RFC 6855, March 2013.
Robert Sparks Oracle 17210 Campbell Road Suite 250 Dallas, Texas 75254-4203 USA