Re: [EAI] I-D Action: draft-ietf-eai-rfc5336bis-11.txt

[Chris Newman <[e-mail]>]

--On July 7, 2011 18:23:52 -0700 [e-mail] wrote:
> 	Title           : SMTP Extension for Internationalized Email
> 	Author(s)       : Jiankang Yao
>                           W. Mao
> 	Filename        : draft-ietf-eai-rfc5336bis-11.txt
> 	Pages           : 20
> 	Date            : 2011-07-07

I've done an extensive "clean slate" review on this document. I found a 
number of issues I consider largely editorial and some I consider 
substantive (in that the decision has technical impact). I've attached my 
full review with editorial notes embedded in the text. Here are the 
substantive issues:

1. Somewhere this needs to say: If a server advertises both UTF8SMTPbis and 
DSN, then that server MUST support UTF-8 in the ORCPT parameter. This also 
has ABNF impact. We need to add:

   ehlo-param  =/ UTF8-non-ascii

to allow UTF-8 in mail, rcpt and data parameters.

2. I would prefer this ABNF rule be removed:

   quoted-pairSMTP  =/ %d92 UTF8-non-ascii
    ; extend the definition of quoted-pairSMTP in RFC5321, section 4.1.2

This is an unnecessary change and makes 5336bis quoting even less 
consistent with 5335bis quoting. Conservative generators should never emit 
\ followed by anything other than \ or double-quote anyway, so adding 
complexity to explicitly allow generation of useless forms is not helpful.

3. I suggest adding a statement to the end of section 3.5:

      SMTP servers are encouraged to detect that recipients can not
      accept internationalized email headers and return an error
      earlier in the transaction whenever possible.

4. In section 3.5, I suggest adding an enhanced status code for the case 
where a U-label can not be converted to an A-label. This is semantically 
quite different from X.6.7 and X.6.9

5. Section 3.7 says the A-label form SHOULD be used. While I don't object 
to that for relay, I believe it should also say that submission clients MAY 
use U-labels.

6. Section 3.7.3:

>   If the messages that include trace fields are sent by an UTF8SMTPbis-
>   aware SMTP client or relay server with the UTF8SMTPbis parameter at
>   MAIL commands, trace field values SHOULD use the U-label form for the
>   internationalized domain name.

      This wording suggests servers need to convert from A-label to
      U-label if a previous server did the wrong thing. I don't think
      that's reasonable. I suggest rewording:

    When an SMTP server adds a trace field to a message that was or
    will be transmitted with the UTF8SMTPbis MAIL FROM parameter, that
    server SHOULD use the U-label form for internationalized domain
    names in that new trace field.

7. Section 3.7.3 needs to say (given the current ABNF):

   The Atom form of the ID clause can contain non-ASCII characters.