2.1.3 Email Address Internationalization (eai)

NOTE: This charter is a snapshot of the 75th IETF Meeting in Stockholm, Sweden. It may now be out-of-date.

Last Modified: 2009-04-03


Harald Alvestrand <harald@alvestrand.no>
XiaoDong Lee <lee@cnnic.cn>

Applications Area Director(s):

Lisa Dusseault <lisa.dusseault@gmail.com>
Alexey Melnikov <alexey.melnikov@isode.com>

Applications Area Advisor:

Alexey Melnikov <alexey.melnikov@isode.com>

Mailing Lists:

General Discussion: ima@ietf.org
To Subscribe: https://www.ietf.org/mailman/listinfo/ima
Archive: http://www.ietf.org/mail-archive/web/ima

Description of Working Group:

Since early in the effort to internationalize domain names, which
resulted in the standards associated with IDNA, it has been
understood that internationalization of email address local parts is
required. At the same time, email address internationalization poses
a series of special problems. Constraints on the interpretation of
local-parts by any system other than the final delivery one make
address encoding nearly impossible. The need to use addresses in both
the email envelope and in header fields, and to do so in ways that are
at least compatible, suggests that this is not a simple and isolated

This working group will address one basic approach to email
internationalization. That approach is based on the use of an SMTP
extension to enable both the use of UTF-8 in envelope address local-
parts and optionally in domain-parts and the use of UTF-8 in mail
headers -- both in address contexts and wherever encoded-words are
permitted today. Its initial target will be a set of experimental
RFCs that specify the details of this approach and provide the basis
for generating and testing interoperable implementations. Its work
will include examining whether "downgrading" -- transforming an
internationalized message to one that is compatible with unextended
SMTP clients and servers and unextended MUAs -- is feasible and
appropriate and, if it is, specifying a way to do so. If it is not,
the WG will evaluate whether the effort is worth taking forward.
Other approaches may be considered by the formation of other
working groups.

Key parts of this effort include extended analyses and, if necessary,
proof of concept in three areas in addition to smooth operation when
all systems and components along a message path have been upgraded to
support the new facilities. They are

o Examination of scenarios for the appearance of these facilities to
users, including ways in which alternate addresses may be
specified if those are needed for downgrading.
o Examination of different locations at which downgrading might be
required and accomplished, differentiating between requirements
and capabilities at the point of origin (at or before the
submission server), those that exist while the message is in
transit, and those that apply after SMTP "final delivery" or in
the logical vicinity or an IMAP or POP server.
o Examination of the "mailing list question", i.e., how a mixture of
traditional and internationalized addresses on a mailing list will
impact message flows, error reports, and delivery notifications in
all plausible combinations of servers and addresses, including
internationalizated and traditional reverse paths.

Once the Experimental RFCs are completed and implemented, the
experience gathered will be evaluated. If the approach is found to
have been successful (using criteria the WG will establish as an
early work item), the WG will be rechartered to update the documents
for processing onto the standards track.

1.6. Deliverables

The following deliverables are foreseen in this charter. The WG
chairs may structure the deliverables into specific documents
or document sets as needed. Adding or removing documents
outside of these deliverables will require a charter update.

o Overview and architecture (Info)
o Interworking scenarios, including the "mailing list question"
o SMTP extensions specification (Exp)
o Header format specification (Exp)
o Downgrading specification in SMTP (Exp)
o Downgrading specification in POP servers (Exp)
o Downgrading specification in IMAP servers (Exp)
o Results and evaluation of experiment (Info)

Going forward, it is possible that the SMTP downgrading specification
will go for Informational due to the difficulty of fully specifying
all necessary behavior.

Additional possible documents suggested:
Advice for MUA implementors (Info)

Goals and Milestones:

Done  Overview/architecture draft first
Done  Interworking scenarios first draft
Done  SMTP Extensions first draft
Done  Header format first draft
Done  Downgrading in IMAP first draft
Done  Downgrading in SMTP first draft
Jun 2006  Overview/architecture draft to IESG
Jun 2006  Interworking scenarios to IESG
Done  Downgrading in POP first draft
Sep 2006  SMTP Extensions to IESG
Sep 2006  Header format to IESG
Sep 2006  Downgrading in SMTP to IESG
Sep 2006  Downgrading in POP to IESG
Sep 2006  Downgrading in IMAP to IESG
Dec 2006  Results and evaluation first draft
Mar 2007  Results and evaluation to IESG
Mar 2007  Group recharter for standards track


  • draft-ietf-eai-imap-utf8-08.txt
  • draft-ietf-eai-pop-07.txt
  • draft-ietf-eai-downgraded-display-02.txt
  • draft-ietf-eai-dsnbis-01.txt
  • draft-ietf-eai-email-clients-00.txt

    Request For Comments:

    RFC4952 I Overview and Framework for Internationalized Email
    RFC5335 E Internationalized Email Headers
    RFC5336 E SMTP Extension for Internationalized Email Addresses
    RFC5337 E Internationalized Delivery Status and Disposition Notifications
    RFC5504 E Downgrading Mechanism for Email Address Internationalization

    Meeting Minutes


    None received.