Yahoo DMARC breakage

Dave Crocker dhc2 at
Wed Apr 9 17:27:55 UTC 2014

On 4/9/2014 10:13 AM, 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?

Their implementation is not 'broken'.

Rather, Yahoo has made a very conscious policy decision.  So the "such 
that" clause of your sentence is correct.  That is, the effect really is 
what you describe.  But it's the result of an informed corporate choice 
rather than software or operations error.

 From background exchanges and Yahoo participation in the development of 
DMARC, I believe they fully understood the technical and operations 
effects of the decision.

Whether it is the 'right' choice is primarily a political debate, and 
I'm not commenting on that.


Dave Crocker
Brandenburg InternetWorking

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