Re: First strawman for UTF-8 headers proposal

At 12:45 AM +0000 11/28/03, Adam M. Costello wrote:
>Paul Hoffman / IMC <[email protected]> wrote:
>
>>  - The dual motivations are to allow UTF-8 everywhere in the headers
>>  and to not bounce any messages just because they originated with UTF-8
>>  headers.
>
>That's a reasonable goal, but later you say:
>
>>  - If the initiator knows the mapping for any recipient (through
>>  caching or an address book), they SHOULD put it in the map header.  If
>>  they don't include a mapping and the message hits a non-UTF-8-HEADERS
>>  SMTP server, the message will bounce.
>
>I don't like that bouncing.
>
>I don't understand why there should be such different policies for the
>domain part and the local part.

As John Klensin has said before, email message processing is *very* 
different than DNS name lookups.

>   For the domain part, your proposal is
>willing to downgrade to an ACE rather than bounce the message.  We might
>as well define an ACE for the local part too, so that there would never
>be a need to bounce messages.

If we add that to my current proposal, then there are *three* 
possible names that a mailbox might have; two of them are readable, 
one of them isn't. I think that is too complicated.

>  > - Updated sending MUAs will create all headers in UTF-8.
>
>What exactly does that mean?  There are details to be worked out.
>Given an old Foo: header with its old ASCII grammar, what exactly is
>the new grammar?  Will canonically (or compatibly) equivalent strings
>necessarily be parsed the same way?

An "old" header has no grammar that produces non-ASCII characters. 
New headers will have new rules.

>  > - Transmission is protected by a new ESMTP command, UTF-8-HEADERS.
>
>Every protocol that carries messages will need an analogous tagging
>mechanism.

I'm not clear what you mean here. Please elucidate.

>There is something that encoded-words can do that your UTF-8 header
>proposal cannot do: encoded-words can indicate the language of the
>text.

I agree with the other folks who said that language tagging is 
probably not needed.

--Paul Hoffman, Director
--Internet Mail Consortium