Network Working Group J. Yao
Internet-Draft X. Lee
Intended status: Informational CNNIC
Expires: March 12, 2010 September 8, 2009
Problems of impeding the use of internationalized email address
draft-yao-eai-problem-00.txt
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Abstract
Many organizations have implemented and tested the internationalized
email systems based on the key RFCs which have been published. This
document points out some problems, which blocks the receiver to
receive the internationalized email address and may impede the
deployment and use of the internationalized email address. Knowing
the problems will help the smooth deployment of Email Address
Internationalization system.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Role of this specification . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Problem statment . . . . . . . . . . . . . . . . . . . . . . . 3
3. Initial Implementation and Test . . . . . . . . . . . . . . . . 4
4. Problems identified in the initial implementation and test . . 4
4.1. SMTP client . . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. Relay Server . . . . . . . . . . . . . . . . . . . . . . . 4
4.3. SMTP Server . . . . . . . . . . . . . . . . . . . . . . . . 4
4.4. Email Filter . . . . . . . . . . . . . . . . . . . . . . . 5
4.5. Firewall . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.6. Mail User Agent . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5
8. Change History . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. draft-yao-eai-problem: Version 00 . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
9.1. Normative References . . . . . . . . . . . . . . . . . . . 6
9.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
The IETF has published five RFCs [RFC4952] [RFC5335] [RFC5336]
[RFC5337] [RFC5504] about internationalized email addresses. CNNIC
has implemented these RFCs, does some tests and identify some
problems during the initial deployment. This document is mainly for
pointing out the problems of blocking the use of internationalized
email address that needs to be considered in the deployment. The
possible soultion to these poroblems can be found in the deployment
document [DeploymentGuidelines].
1.1. Role of this specification
The framework document specifies the requirements for, and describes
components of, full internationalization of email address. The EAI
SMTP extension document [RFC5336] specifies the SMTP extension to use
the internationalized email address. The EAI header document
[RFC5335] allows the internationalized email address headers. The
EAI downgrade document [RFC5504] addresses how to downgrade to be
compatible with the current non-EAI-system. The deployment document
[DeploymentGuidelines] addresses the possible solution to the
problems identified in this document.
1.2. Terminology
All the specialized terms used in this specification are defined in
the framework document [RFC4952], the EAI SMTP extension document
[RFC5336], the EAI header document [RFC5335] and the base Internet
email specifications [RFC5321] [RFC5322]. In particular, the terms
"ASCII user", and "i18mail user" are used in this document according
to the definitions in the framework one.
[[anchor3: NOTE TO RFC EDITOR: Please remove the following text
before publication.]]
Some ideas of this specification is being discussed on the EAI
mailing list. See https://www1.ietf.org/mailman/listinfo/ima for
information about subscribing. The list's archive is at
http://www1.ietf.org/mail-archive/web/ima/index.html.
2. Problem statment
If the i18mail user sends the message with the internationalized
email address which is successfuly received by the receiver without
any downgrading, we define such sending as the successful sending of
internationalized email address. If the i18mail user sends the
message with the internationalized email address because the SMTP
client or mail user agent or submission server can not support
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internationalized email address, refuse to send the message and
result into the failure of sending of internationalized email
address, we call it the failure operation. In other situation, we
call it the failure of the sending of internationalized email
address. In order to have more successful sending of
internationalized email address, less downgrade operation or failure
operation, we need identify the problems which block the successful
sending of internationalized email address.
3. Initial Implementation and Test
As far as we know, CNNIC, TWNIC, AFILIAS, JPRS and NIDA have
implemented the [RFC5335], [RFC5336], [RFC5504]. CNNIC updates the
Postfix source code to support EAI. [RFC5504]. The openweb mail is
used for EAI clients. Both TWNIC and AFILIAS update Sendmail. JPRS
uses C language to implement EAI. NIDA uses python to implement it.
CNNIC/TWNIC/JPRS/AFILIAS/NIDA have the co-tests based on the scenario
documnent. We summarize the following problems identified in our
tests which may block the successful sending of internationalized
email address.
4. Problems identified in the initial implementation and test
The key aim of EAI WG is to promote the use of internationalized
email address. In order to have the smooth operation of EAI system
and have the success use of internationalized email address, we
should address all the following problems before deploying the EAI
systems.
4.1. SMTP client
If the SMTP client or submisstion server is not ready to support
[RFC5335] and [RFC5336], the EAI mail user agent can not submit the
email message to the SMTP client. So it is impossible to receive the
internationalized email address from the i18mail user.
4.2. Relay Server
If the relay server has not EAI-capability, it will not accept any
UTF8SMTP message. Some downgrading may happen.
4.3. SMTP Server
The SMTP server gets the message from the SMTP client. If the SMTP
server which is the final delivery server has not EAI-capability, the
receiver can not get the i18n messages.
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4.4. Email Filter
Many email receivers have installed the email filters. The non-EAI-
capability filiters may regard EAI messages as the rubbish and drop
them immediately.
4.5. Firewall
The traditional fireall specified in [RFC2979] will not understand
the keyword "UTF8SMTP", These actions will lead to unnecessary
message failure, and the SMTP connection will be cut off by the
firewall.
4.6. Mail User Agent
Most non-EAI-capability Mail User Agent (MUA) can not support
internationalized email address. It will regard the
internationalized email address as illegal and refuse to send the
message on behalf of the i18nmail user.
5. IANA Considerations
There is no IANA consideraton.
6. Security Considerations
See the extended security considerations discussion in the framework
document [RFC4952].
7. Acknowledgements
Many ideas are from the discussion in the list ima@ietf.org. John C
Klensin has done a lot of reasearch on ASCII email address and
internationalized email address. I got many significant words or
ideas from him. Many friends and experts in the EAI WG help us to
produce the valuable ideas. Many organizations including CNNIC,
TWNIC, JPRS, NIDA, AND AFFLILIAS have implemented EAI systems. These
organizations have already done a lot of inter-operating testing.
8. Change History
[[anchor13: RFC Editor: Please remove this section.]]
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8.1. draft-yao-eai-problem: Version 00
o identifying the problems during EAI implementation and initial
tests"
9. References
9.1. Normative References
[ASCII] American National Standards Institute (formerly United
States of America Standards Institute), "USA Code for
Information Interchange", ANSI X3.4-1968, 1968.
[DeploymentGuidelines]
Yao, J. and X. Lee, "Guidelines for Internationalized
Email Deployment", draft-yao-eai-deployment-03.txt (work
in progress), September 2009.
[RFC1652] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
Crocker, "SMTP Service Extension for 8bit-MIMEtransport",
RFC 1652, July 1994.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2979] Freed, N., "Behavior of and Requirements for Internet
Firewalls", RFC 2979, October 2000.
[RFC3461] Moore, K., "Simple Mail Transfer Protocol (SMTP) Service
Extension for Delivery Status Notifications (DSNs)",
RFC 3461, January 2003.
[RFC3463] Vaudreuil, G., "Enhanced Mail System Status Codes",
RFC 3463, January 2003.
[RFC3490] Faltstrom, P., Hoffman, P., and A. Costello,
"Internationalizing Domain Names in Applications (IDNA)",
RFC 3490, March 2003.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", RFC 3629, November 2003.
[RFC4409] Gellens, R. and J. Klensin, "Message Submission for Mail",
RFC 4409, April 2006.
[RFC4952] Klensin, J. and Y. Ko, "Overview and Framework for
Internationalized Email", RFC 4952, July 2007.
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[RFC5321] Klensin, J., "Simple Mail Transfer Protocol", RFC 5321,
October 2008.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
October 2008.
[RFC5335] Abel, Y., "Internationalized Email Headers", RFC 5335,
September 2008.
[RFC5336] Yao, J. and W. Mao, "SMTP Extension for Internationalized
Email Addresses", RFC 5336, September 2008.
[RFC5337] Newman, C. and A. Melnikov, "Internationalized Delivery
Status and Disposition Notifications", RFC 5337,
September 2008.
9.2. Informative References
[DeploymentTests]
YAO, J., YEE, J., KAO, M., and D. KIM, "Discussion, Test
and Evaulation for EAI deployment",
draft-yao-eai-tests-00.txt (work in progress),
August 2009.
[RFC5504] YONEYA, Y., Ed. and K. Fujiwara, Ed., "Downgrading
mechanism for Internationalized eMail Address", RFC 5504,
3 2009.
Authors' Addresses
Jiankang YAO
CNNIC
No.4 South 4th Street, Zhongguancun
Beijing
Phone: +86 10 58813007
Email: yaojk@cnnic.cn
Xiaodong LEE
CNNIC
No.4 South 4th Street, Zhongguancun
Beijing
Phone: +86 10 58813020
Email: lee@cnnic.cn
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