Yahoo DMARC breakage

Wed Apr 9 16:26:22 UTC 2014

On Wed, Apr 09, 2014 at 07:13:47AM -0800, Royce Williams wrote:
> Am I interpreting this correctly -- that Yahoo's implementation of
> DMARC is broken, such that anyone using a Yahoo address to participate
> in a mailing list is dead in the water?

Yes.  It seems that Yahoo wasn't content with just breaking Flickr [1]
but decided to branch out into email as well.  John Levine's comments
(in the first link you provided) have been, I think, the most articulate 
on the subject.

The worst part of this is (a) it creates massive problems for everyone
running mailing lists and (b) it doesn't solve any problems for anybody,
including Yahoo and its users.

Mitigation tactics vary, but one is to put everyone using a yahoo.com
address on moderation, using whatever mechanism the mailing list manager
(e.g. Mailman, majordomo, etc.) provides.  Another is to encourage people
with Yahoo accounts to move elsewhere.

(There's nothing "wrong" with DMARC, per se, although I remain somewhat
skeptical about its widespread/long-term utility.  What's "wrong" here
is that it's been badly misapplied to a use case that it doesn't fit.
To borrow a line from Zathras, "This...is wrong tool.")

---rsk

[1] http://boingboing.net/2014/04/07/restoring-cc-attribution-to-fl.html