Subject: Re: [dmarc-ietf] DMARC2 & SPF Dependency Removal

From: "Murray S. Kucherawy" <[email-masked]>
Date: Fri, 9 Jun 2023 22:35:03 -0700

On Fri, Jun 9, 2023 at 8:49 AM Alessandro Vesely <[email-masked]> wrote:

> On Fri 09/Jun/2023 16:07:07 +0200 Murray S. Kucherawy wrote:
> > And signing software shouldn't be mutating messages ever (other than
> adding
> > signatures, of course).
>
> Section 5.3, Normalize the Message to Prevent Transport Conversions, gives
> different advice.  UTF-8, though, seems to be subject to mutating
> fashions;
> conversion to 7-bit form, IMHO, makes sense only if it is base64.  Quoted
> printable is messy and prevents recovery after MLM transformation.
>

You were previously talking about inserting ">" before a line starting
"From ", which is typically done on delivery when writing to an
mbox-formatted mailbox file, because in that format, "From " at the front
of a line has a specific meaning (i.e., "this is a new message").  If that
insertion is happening in transport, then a local mailbox convention is
leaking out into the transport environment, which means something is
misconfigured, and all bets are off.

In any case, it is not a transport conversion anticipated by the section
you're quoting, so I've no idea why a DKIM signer might opt to handle it
specially.

-MSK, participating