Re: [ietf-822] utf8 messages

[Alessandro Vesely <[e-mail]>]

On Wed 13/Aug/2014 10:00:32 +0200 Brandon Long wrote:
> Adding under-specified 6532 messages to the mix means that we are now
> generating messages that can easily slip into the second pool.  We try
> our best to only generate well specified / syntactically correct
> messages.. "be conservative in what you send" and all, but now we're
> being forced to take steps that we know will increase the number of
> failures.  We're attempting to adjust our heuristics to compensate, but
> that seems like a poor response compared to making the messages be well
> specified.

QUESTION:  UTF8 compliant receivers may want to reject utf8 messages for
certain recipients who cannot upgrade their readers.  But thanks to the
specific reply code, retrying doesn't seem to be a problem if the
message can be downgraded trivially.  So, is it advisable to *always*
use the SMTPUTF8 extension if both peers support it?

That habit would produce valid 6532 messages which are also valid 5322,
hence trivially downgradable.  Section 3.4 of RFC 6531 says:

                                          If the SMTPUTF8-aware SMTP
   client is aware that neither the envelope nor the message being sent
   requires any of the SMTPUTF8 extension capabilities, it SHOULD NOT
   supply the SMTPUTF8 parameter with the MAIL command.

Now, having an external marker would make the client aware, and thus
inhibit homogeneous treatment of messages.  That strategy seems to be
good if only a few servers switch to utf8...  If I were Google, I'd
assume they follow.

Ale