At 02:22 PM 7/14/2002 -0400, John C Klensin wrote:
First of all, I don't find, anywhere in the document, a statement
that the originator, in attempting to use CONNEG, is authorizing
any intermediate MTA that might touch the message to alter its
content.
For a specification that is designed to permit a sending agent to know how
to tailor the form of a content, it is difficult to imagine what benefit
there can be in having that specification contain a statement saying that
an implementation is "authorized" to tailor the form of that content.
Nor do I find in the "security considerations" an
explanation of that authorization and the associated risks.
You clearly have a better sense of this issue than I do, since I do not see
that there is a problem.
So, feel free to offer some text.
We have
typically tried to keep that transmission stream as opaque to
message content as possible.
Yup. It sure is scary to try to do new things.
Except when there is a well-established basis for doing them.
I am not inclined to dismiss that established basis solely because it came
from a non-IETF effort, particularly given the scale of success of that
prior work.
But, unless I read the above incorrectly, you are suggesting that
* Hence intermediate/relay MTAs have the right/authority
to make content changes based on their inferences about
what the receiver wants.
Let's try to stay on the current topic. Arguing about generic principles
and then trying to dismiss current work based on some subtle variation in
interpretations of that abstract discussion is not going to be productive.
You might want to review prior work on interprocess communication, which
explored trade-offs between a "sender makes right" model and a "receiver
makes right system".
The significant difference between esmtp/connect and multipart/alternative
is exactly this distinction.
(Hint: sender makes right has nearly always been the preferred IETF
choice. esmtp/conneg is sender makes right.)
Could you explain what you did mean?
What I mean is very simple:
The behavior that is specified in esmtp/conneg is a careful
increment in functionality and is based on extensive prior experience and
is known to be useful.
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Dave Crocker <mailto:dave(_at_)tribalwise(_dot_)com>
TribalWise, Inc. <http://www.tribalwise.com>
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