Subject: [Uta] Ben Campbell's Yes on draft-ietf-uta-smtp-require-tls-07: (with COMMENT)

From: Ben Campbell <[email-masked]>
Date: Wed, 20 Feb 2019 19:50:00 -0800

Ben Campbell has entered the following ballot position for
draft-ietf-uta-smtp-require-tls-07: Yes

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COMMENT:
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Thanks for this. I am balloting "yes", but I have a couple of questions. (The
first would border on a DISCUSS, but I suspect I am reading something wrong):

- I am confused about the handling of bounce messages. §4.1 says the following:

"Upon receipt of the REQUIRETLS option on a MAIL FROM command during
the receipt of a message for which the return-path is not empty
(indicating a bounce message), an SMTP server MUST tag that message
as needing REQUIRETLS handling."

... which seems to exempt bounce messages from REQUIRETLS tagging. But §5 says:

"Non-delivery ("bounce") messages usually contain important metadata
about the message to which they refer, including the original message
header. They therefore MUST be protected in the same manner as the
original message. All non-delivery messages resulting from messages
with the REQUIRETLS SMTP option, whether resulting from a REQUIRETLS
error or some other, MUST also specify the REQUIRETLS SMTP option
unless redacted as described below."

... which seems to require bounce messages to _not_ be exempt from tagging.

What am I missing?

§6: "REQUIRETLS users SHOULD be made aware
of this limitation so that they use caution when sending to mailing
lists and do not assume that REQUIRETLS applies to messages from the
list operator to list members."

Does this mean a user agent needs to know if a message destination is a list so
that it can make the user aware?

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From: Jim Fenton <[email-masked]>
Date: Tue, 26 Feb 2019 11:59:21 -0800

The first paragraph you quote refers to the requirement to preserve
REQUIRETLS tagging for messages being relayed. The second refers to the
requirement to tag bounce messages at the point where the bounce message
is created, unless the bounce message has been redacted. The exemption
of bounce messages in Section 4.1 seems to be wrong, and probably is a
relic from earlier language that did not handle bounce messages fully.

I'd propose to change 4.1 to say:

"Upon receipt of the REQUIRETLS option on a MAIL FROM command during the
receipt of a message, an SMTP server MUST tag that message as needing
REQUIRETLS handling."

> that it can make the user aware?

No, this is a user education issue not a protocol feature, and should
not be using the normative SHOULD.

-Jim

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From: Ben Campbell <[email-masked]>
Date: Tue, 26 Feb 2019 14:27:56 -0600

Sounds good, thanks!

Ben.

> On Feb 26, 2019, at 1:59 PM, Jim Fenton <[email-masked]> wrote:
>