Email World Updates: IMAP, Lemonade, and Sieve Innovations in Email Communication

1. Alexey Melnikov <alexey.melnikov@isode.com> What's new in the Email WorldIMAP/LEMONADE/SIEVE(no DKIM or EAI)

2. IMAP is message access protocol, designed to make clients easier Tasked to produce extensions to IMAP (RFC 3501), such as: Sorting, threading, and viewing Access Control Lists Message-level annotations I18N IMAP building blocks to build cool toys IMAPEXT WG

3. LEMONADE WG • Lemonade is tasked to provide a set of enhancements and profiles of Internet email submission, transport, and retrieval protocols to facilitate operation on platforms with constrained resources, or communications links with high latency or limited bandwidth. • Lemonade Profile recently published (RFC 4550) • Forward-without-download • Push Email (IMAP IDLE) • Quick Flag Changes Resynchronization (CONDSTORE) • Reduction of bandwith/round-trips

4. [Soon to be] completed work in IMAPEXT WG • April 2006 - Collected Extensions to IMAP4 ABNF (RFC 4466) • October 2006 - Comparators (Internet Application Protocol Collation Registry) - draft-newman-i18n-comparator-14.txt - in RFC editor queue • October 2006 - IMAP4 LIST Command Extensions (draft-ietf-imapext-list-extensions-18.txt) - in RFC editor queue, waiting for IMAP I18N document to finish • IMAP ANNOTATE Extension (draft-ietf-imapext-annotate-16.txt) - in IESG evaluation • IMAP METADATA Extension (draft-daboo-imap-annotatemore-10.txt) – per mailbox annotations • The IMAP ENABLE Extension (draft-gulbrandsen-imap-enable-00.txt)

5. Recently completed work in IMAPEXT/LEMONADE WGs • Dec 2005 - IMAP4 ACL Extension (RFC 4314) • Dec 2005 - Update to UIDPLUS (RFC 2359), RFC 4315 • Jun 2006 - IMAP Extension for Conditional STORE Operation or Quick Flag Changes Resynchronization (RFC 4551) • Apr 2006 - IMAP CATENATE Extension (RFC 4469) • May 2006 - Message Submission BURL Extension (RFC 4468) • May 2006 - IMAP - URLAUTH Extension (RFC 4467)

6. Forward-without-download

7. Lemonade interop eventOctober 2006, London • 4 servers • 2 clients (more promised soon) • Bugs found, but things mostly work • IMAP URL • Some [mostly minor] issues are found in F-W-D, CONDSTORE documents

8. Relative-path IMAP URLs • draft-ietf-lemonade-rfc2192bis-02.txt • Needs review by URI experts • Relative-paths are only used in IMAP CATENATE so far • IMAP mailbox hierarchy separator can be different in different server: • INBOX.Apple.Green • INBOX/Apple/Green • What is the meaning of: • ..;UIDVALIDITY=385759045/;UID=20 • .;UIDVALIDITY=385759045/;UID=20/..

9. Future work • IMAPEXT • I18N document • SORT/THREAD • LEMONADE • IMAP/SMTP compression • Quick reconnect • Content conversion • Improvements to SEARCH command • Filtered views • Controlling in-band/out-band notifications • Multimedia streaming

10. IMAP Internationalization • draft-ietf-imapext-i18n-07.txt [expired] • draft-ietf-eai-imap-utf8-00.txt • Issues • Internationalized error responses • Something similar is needed in SMTP • Usernames/passwords • Frequently used as email addresses • Mailbox names • Domains, Addresses and Mail Headers • EAI WG • IMAP keywords (?) • ...

11. IMAP/SMTP compression • Works in the same way as TLS or SASL security layer • Stop gap until TLS compression is deployed in OSes • IMAP document is past WGLC • SMTP needs to be written • Would there be enough saving to make it worthwhile

12. Quick reconnect • Goal: minimize reconnection cost when connectivity is poor • IMAP: was a server side mechanism at first • SMTP: revise RFC 1845 (SMTP Service Extension for Checkpoint/Restart) (?) • This might be less of an issue when BURL (F-W-D) is deployed

13. Content conversion • Content conversion (draft-ietf-lemonade-convert-05) • E.g. convert a Word attachment to PDF • Similar to recently done IMAP BINARY extension • In WGLC now

14. Various improvements to SEARCH • Improvements to SEARCH command • Aug 2006 - IMAP4 extension to SEARCH command for controlling what kind of information is returned (draft-melnikov-imap-search-ret-03.txt) - in RFC editor queue • Virtual Mailboxes / Persistent searches (next slide) • draft-melnikov-imap-search-res-03.txt • draft-melnikov-imapext-filters-00.txt • draft-melnikov-imapext-multimailbox-search-01.txt • draft-ietf-lemonade-search-within-02.txt

15. Filtered Views • Two proposals: • draft-cridland-imap-context-00.txt • Persistent searches + paged results • draft-ietf-lemonade-vfolder-01.txt • Virtual Mailboxes

16. Controlling in-band notifications for mailstore events • Push email (IMAP IDLE, RFC 2177) works great(*) and is widely deployed • However servers report different events • Need a catalog of events • draft-ietf-lemonade-msgevent-00.txt • Need a way for the client to request specific events • draft-gulbrandsen-imap-notify-01.txt

17. Other bandwidth/round trip related optimizations in IMAP/SMTP • QTLS (replacement for STARTTLS in SMTP) • IMAP SASL-IR • IMAP QRESYNC

18. Forward-without-download for encrypted content • IMAP server can't do that, as it doesn't know the key • Security implications are serious • Do you trust your own IMAP server?

19. SIEVE • Mail Filtering language, that can run in MTAs, MDAs, MUAs • Selected items from the recently completed work: • Sieve Extension: Variables • Sieve Email Filtering: Vacation Extension • Spamtest extension

20. Future SIEVE work • Extended abilities to process/manipulate email messages • Sieve Email Filtering: Body Extension • Sieve Email Filtering: Editheader Extension • SIEVE Email Filtering: MIME part Tests, Iteration, Replacement and Enclosure • SIEVE Email Filtering language - reject extension • Needs ability to send UTF-8 error responses in SMTP • Sieve Extension: Notifications

21. Important Informational documents • Internet Mail Architecture (draft-crocker-email-arch-05.txt) • Deployment Considerations for lemonade-compliant Mobile Email (draft-ietf-lemonade-deployments-03.txt)