Subject: Re: [EAI] draft-ietf-eai-smtpext-02.txt ( draft-ietf-eai-utf8headers-02.txt )

From: Kari Hurtta <[email-masked]>
Date: 01 Nov 2006 07:10:34 +0200

Kari Hurtta <[email-masked]> writes:

> draft-ietf-eai-smtpext-02.txt:
> 
> |  Assuming that the server advertises UTF8SMTP and 8BITMIME, and at
> |   least one non-ASCII address, with or without ALT-ADDRESS, the precise
> |   interpretation of these parameters on the MAIL command is:
> |   1.  Headers are in UTF-8, body parts are in ASCII.
> |   2.  Headers are in UTF-8, some or all body parts contain 8-bit line-
> |       oriented data.
> |   3.  Headers are in UTF-8, some or all body parts contain binary data
> |       without restriction as to line lengths or delimiters.
> 
> So model is following:
> 
>    Indication for internationalized email is
>       Header-Type: UTF8
> 
>    header field on mail DATA.
> 
> let's compare this to model of 8-bit MIME email model:
> 
>    Indication for 8-bit (MIME)  emila is
>       BODY=BITMIME
> 
>    parameter on MAIL -command
> 
>    However there is also
>       Content-Transfer-Encoding: 8bit
> 
>    header field on mail DATA,  but 8BITMIME extension did
>    not select that for indication.
> 
> 
> 
> So perhaps it make sense to compare what are differences
> on these two situations?
> 
> Question is: 
> 
>    Why 8BITMIME needed BODY=BITMIME parameter for MAIL -command
>    when same information is available on email header
>    fields ?
> 
>    Why UTF8SMTP does not need parameter for MAIL -command,
>    but instead is relying email header field about that.
> 
> 
> 
> I do not say that there is something wrong,
> but I ask reasoning of selections.

One reason, why perhaps 
         MAIL FROM:<xxxxx> BODY=8BITMIME

was used as indication instead of

         DATA
         ....
         Content-Transfer-Encoding: 8bit

is that MAIL -command occur before RCPT -command.

Therefore SMTP recipient can reject RCPT TO -command,
if it knows that it can not downgrade email.

However RFC 1652 do not confirm that reason.

To UTF8SMTP sequence is

         MAIL FROM:<7-bit-address@domain1>
         RCPT TO:<7-bit-localpart@domain2>
         RCPT TO:<7-bit-localpart@domain3>
         DATA
         Header-Type: UTF8
         ...
         Subject: Ääkkösiä
         ...
         Content-Ttype: text/plain
         Content-Transfer-Encoding: 7bit

         7-bit-text
         .

domain2 is known to support UTF8SMTP and domain3
is known to not support UTF8SMTP.

/ Kari Hurtta

_______________________________________________
IMA mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ima