[dmarc-discuss] Mailinglists: Sender-Header

Patrick Rauscher listen at prauscher.de
Thu Jun 12 07:05:31 PDT 2014


Hello,

unfortunatly I could not grab all archives, but I could not find the
answer to my question in the FAQ, so maybe you can help me.
The main problem of DMARC in combination with mailinglists are the
From-Header, right?
If we leave it with the original value we cannot change any part of the
Mail due to DKIM. If we change it, we get problems with replys.

So how about either using good old Sender-Header in DMARC/DKIM for
Domain-Verification or add a new Header containing the original
From-Header and overwriting the From-Header.

In both cases the Sender-Header / new From-Header would have to be set
by the LIST-software to an local address (like the address of the list).
DKIM/DMARC-Checks would work on this address and let mails pass.

I'd prefer setting the Sender-Header, since this
a) has no need for a new Header and
b) makes more sense: DKIM/DMARC shall check if the mail originates from
   where it claims to come from. This is stored in the Sender-Header (if
   present).

The con to this approach is, that anybody could then spoof the
From-Headers. But I think it's the MUAs job to show who has sent the
mail. Maybe this could be an additional check in Spamcheckers or so.

To return to my question: Why does DKIM/DMARC use the From-Header, if
Sender-Header is present?

Thank you,
prauscher



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