Re: What I've been wondering about the DMARC problem

"Murray S. Kucherawy" <superuser@gmail.com> Fri, 18 April 2014 15:45 UTC

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References: <534ED376.8060303@bluepopcorn.net> <20140418013433.2763.qmail@joyce.lan>
Date: Fri, 18 Apr 2014 08:45:44 -0700
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Subject: Re: What I've been wondering about the DMARC problem
From: "Murray S. Kucherawy" <superuser@gmail.com>
To: John Levine <johnl@taugh.com>
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Cc: Jim Fenton <fenton@bluepopcorn.net>, ietf <ietf@ietf.org>
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On Thu, Apr 17, 2014 at 6:34 PM, John Levine <johnl@taugh.com> wrote:

> >"If the RFC5322.From domain does not exist in the DNS, Mail Receivers
> >SHOULD direct the receiving SMTP server to reject the message."
>
> As far as I can tell, that bit of poor advice hasn't been implemented.
>

Why is that poor advice?  It's not uncommon for an MTA receiving mail to
confirm that the message is replyable, at least insofar as an A and MX are
available for whatever comes after the "@".

-MSK


>
> PS: I did a few experiments, and putting two addresses on the From:
> line works remarkably well to avoid inappropriate policy failures,
> e.g.
>
>  From: Marissa <marissam@yahoo.com>om>, foo-list@ietf.org
>  Subject: whatever
>  ...
>
>
Huh, interesting.  Likely accidental, alas.

-MSK