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Re: [Ietf-dkim] Question about lone CR / LF

"Murray S. Kucherawy" <superuser@gmail.com> Sat, 03 February 2024 22:08 UTC

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From: "Murray S. Kucherawy" <superuser@gmail.com>
Date: Sat, 03 Feb 2024 14:08:19 -0800
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To: John R Levine <johnl@taugh.com>
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Subject: Re: [Ietf-dkim] Question about lone CR / LF
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On Sat, Feb 3, 2024 at 1:54 PM John R Levine <johnl@taugh.com> wrote:

>
> > It also optionally does LF to CRLF translation.  I'm fairly certain this
> is
> > to accommodate local/human SMTP injections since humans can't be expected
> > to type CRLFs when entering manual tests from a shell. ...
>
> Unix MTAs strip out the CR in CRLF, often on the way in, so by the time
> opendkim sees the message, the line endings are just LF.
>

That might be true when it's handing a message to an LDA, but it's not true
for SMTP ingress filters.  For milter, CRs are preserved in the body, so
opendkim sees exactly what came in over the wire.

https://pythonhosted.org/pymilter/milter_api/xxfi_body.html

-MSK

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