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Re: First strawman for UTF-8 headers proposal


At 12:45 AM +0000 11/28/03, Adam M. Costello wrote:
Paul Hoffman / IMC <phoffman@xxxxxxx> 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