smtp extension for internationalized email address yao jiankang 2006 cnnic
TRANSCRIPT
SMTP extension for internationalized email
addressYAO Jiankang2006 CNNIC
Main Changes from -00
draft-yao-ima-smtpext-02.txt (thanks a lot for all the comments to version 00)
Add Extended Mailbox Address Syntax
Add the “ATMOIC” parameter and introduction
Add the specification of uses of “ALT-ADDRESS” and “ATOMIC” parameters
Add the message header question description
Add the mailing list question description
What is the internationalized eMail Address?
Mailbox = Local-part "@" Domain
Local-part = Dot-string / Quoted-string ; MAY be case-sensitive
Dot-string = Atom *("." Atom)
Atom = 1*Ucharacter Ucharacter = <any UNICODE character, except ASCII
characters that are not permitted in "atext" >
Quoted-string = DQUOTE *qcontent DQUOTE
Domain = (sub-domain 1*("." sub-domain)) / address-literal sub-domain = Let-dig [Ldh-str] / <any internationalized domain label specified by IDNA>
Framework for the Internationalization
Extension 1. The EHLO keyword value associated with
this extension is "IEmail"; 2. No parameter values are defined for this
EHLO keyword value. 3. Two optional parameters are added to th
e SMTP MAIL and RCPT commands. The first parameter is named as ALT-ADDRESS. The second is ATOMIC.
4. No additional SMTP verbs are defined by this extension.
5. Servers offering this extension MUST provide support for, and announce, the 8BITMIME extension.
The ALT-ADDRESS and ATOMIC parameter
If the IMA extension is offered, the syntax of the SMTP MAIL and RCPT commands is extended to support both the optional "ALT-ADDRESS" and "ATOMIC" parameter.
The "ALT-ADDRESS" requires an all-ASCII address, which may be set by sender or some algorithmic transformation.
The “ATOMIC” parameter indicates whether the IMA can be safely transformed into ACE
The use of the ALT-ADDRESS will be according to the following priority if SMTP servers can not support IMA capability.
1. If the sender has already set the ALT-ADDRESS value in spite of the value of ATMOIC, the client SMTP server will use this address as the emai address.
2. If the ALT-ADDRESS value is not set by the sender but the value of ATOMIC is 'y', the sender SMTP server can apply some algorithmic transformation such as punycode.
3. If the ALT-ADDRESS value is not set by the sender and the value of ATOMIC is 'n' which means that the local part of IMA can not be converted to the ASCII email address safely, the email must be bounced to the original sender.
