[dmarc-discuss] multiple from

Tim Draegen tim at eudaemon.net
Tue Jul 16 06:31:41 PDT 2013


On Jul 16, 2013, at 9:19 AM, Andreas Schulze <sca at andreasschulze.de> wrote:
> 
> Hello,
> 
> "The domain name extracted from a message's RFC5322.From field is the primary identifier in the DMARC mechanism."
> 
> RFC5322, Secion 3.6.2 allow multiple originators in a from field. In this case there must be a sender field
> present.
> 
> I did not find any statements about this situation in the draft.
> I expect the primary identifier would be the RFC5322.Sender, right?
> 
> Or is dmarc only applicable if RFC5322.From has exactly one originator?
> Also that isn't declared in the draft.
> 
> Anyway: I think multiple RFC5322.From are nice and there may be academical use cases
> but it adds unnecessary complexity in todays applications.
> Maybe it could be "defined" out of the way :-)
> 
> Andreas

Hi Andreas,

This section of the spec mentions multiple Froms, it's a tricky thing:

	http://tools.ietf.org/html/draft-kucherawy-dmarc-base-01#section-10.1

About the Sender: header:

	http://tools.ietf.org/html/draft-kucherawy-dmarc-base-01#appendix-A.3

FWIW, allowing multiple "policy keys" adds quite a bit of complexity.  Which one takes precedent?  Does allowing multiple keys allow a domain to send on behalf of another even though the other domain publishes an explicit reject policy?  Big can of worms for no benefit.

HTH,
=- Tim





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