Re: Do we actually want to do anything about DMARC?

Theodore Ts'o <tytso@mit.edu> Mon, 15 August 2016 13:01 UTC

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Date: Mon, 15 Aug 2016 09:01:06 -0400
From: Theodore Ts'o <tytso@mit.edu>
To: Alessandro Vesely <vesely@tana.it>
Subject: Re: Do we actually want to do anything about DMARC?
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On Mon, Aug 15, 2016 at 11:31:16AM +0200, Alessandro Vesely wrote:
> On Mon 15/Aug/2016 03:22:08 +0200 John Levine wrote:
> > 
> > My form is marissa@yahoo.com.dmarc.fail, but if wildcard MX records
> > are scary, it could be marissa-yahoo.com@fwd.ietf.org.  Having done
> > this before, I know it's not terribly hard, and I'd be happy to help
> > make it work.
> 
> Marissa@yahoo.com.MANUALLY.REMOVE.THE.TRAILING.PARTS would involve even
> less work and worries.  IMHO, it is not so much its forcing recipients
> to refurbish their wit in order to discern phishes, as its rendering the
> From: field meaningless, which troubles this workaround's viability.

>From what John has said, he's actually made the from field work:

% dig -t mx dmarc.fail +nocomments

; <<>> DiG 9.10.3-P4-Debian <<>> -t mx dmarc.fail +nocomments
;; global options: +cmd
;dmarc.fail.			IN	MX
dmarc.fail.				3599	IN	MX	20 mail1.iecc.com.
;; Query time: 188 msec
;; SERVER: 192.168.86.1#53(192.168.86.1)
;; WHEN: Mon Aug 15 08:58:07 EDT 2016
;; MSG SIZE  rcvd: 69


I do wonder how he deals with the spam reputation problem of his
forwarding server if too many spammers try to send mail to
marissa@yahoo.com.dmarc.fail --- I assume he must do a lot of
anti-spam filtering and is refusing to forward stuff which is spam?

Hopefully he's using a more intelligent spam filter than Gmail is,
though.  :-)

	https://plus.google.com/+DavidMiller/posts/ifyNptbyxs1

Maybe spammers are starting to use patches as filler?  Who knows.  :-(

Next thing you know, maybe they'll start using excerpts from I-D's,
and then where will the IETF be?

						- Ted