Re: [ietf-smtp] broken signatures, was Curious

John C Klensin <> Tue, 21 July 2020 22:12 UTC

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Date: Tue, 21 Jul 2020 18:12:30 -0400
From: John C Klensin <>
To: Paul Smith <>,
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Subject: Re: [ietf-smtp] broken signatures, was Curious
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--On Tuesday, 21 July, 2020 22:41 +0100 Paul Smith
<> wrote:

> The former ones tell me something. It may or may not be that
> useful. It may nor may not be true, but it tells me something.
> The latter ones tell me (the recipient) nothing at all. I'm
> honestly not sure why the latter data is in the headers at all.
> It *may* be that if I ask for support from Paypal about an
> email, they'll ask me 'What was the
> "X-PP-Email-Transmission-Id'' header in that message? But I
> seriously doubt that would happen. If it did, then adding that
> header is OK, otherwise, no. In any case, the Message-ID
> should be sufficient for them to trace it if that's what they
> need to do.
> The former set may be more useful if it was tagged with WHICH
> server added those headers, but that's it.

Is it the case that, if we wanted to make these useful, we'd be
considering a way to make those fields into trace fields, with
all of the time-stamping and server (or other supplying entity)
information that implies?    Non-trivial work and something that
would certainly have to be done as a new Proposed Standard or
Experimental spec, not in 5321bis, but maybe an interesting

FWIW, it is a question: I have no idea whether it would be a
good idea.