Re: [Uta] Benjamin Kaduk's Discuss on draft-ietf-uta-smtp-require-tls-07: (with DISCUSS and COMMENT)

[Jim Fenton <[e-mail]>]

On 2/27/19 3:45 PM, Viktor Dukhovni wrote:
> On Tue, Feb 26, 2019 at 03:26:05PM -0800, Jim Fenton wrote:
>
>>>    If a REQUIRETLS message is bounced, the server MUST behave as if
>>>    RET=HDRS was present as described in [RFC3461].  If both RET=FULL and
>>>    REQUIRETLS are present, the RET=FULL MUST be disregarded and MAY be
>>>    transformed to RET=HDRS on relay.  The SMTP client for a REQUIRETLS
>>>
>>> If the MAY is not taken, will the next hop be obligated to detect that this
>>> is a bounce and apply the preceding MUSTs?  If not, perhaps this also
>>> should be a MUST?
>> It seems like it should, yes.
> Actually, absolutely not.  It is not the job of email *relays* to
> modify the message content, and they must not be obligated to do
> so.  Message modifications break DKIM signatures, and require
> content processing logic that relays are not expected to support.
>
> The bounce is constructed as a new message at the server that
> encounters the initial delivery problem, it is *only* at *that*
> point that the decision can be made to include or exclude the
> original message body in the bounce.
>
Good point; so we should just remove the phrase "and MAY be transformed
to RET=HDRS on relay"? It contradicts the previous MUST anyway.