[dmarc-discuss] How does *this* mailing list interact with dmarc?

Steven Chamberlain steven at pyro.eu.org
Wed Jun 20 06:20:52 PDT 2012


Hi,

When I send this mail to the list, I would expect it to be forwarded to
its subscribers keeping the RFC5322.From address of steven at pyro.eu.org

The dmarc.org domain has an SPF record that should authenticate the
RFC5321.MailFrom of forwarded mails, but this will not be in alignment
with RFC5322.From as per DMARC 4.2.2. and so is not considered.

>From the list archives it appears there would be some list information
and unsubscribe instructions appended to the message body, which would
cause my DKIM signature not to verify.  Even if the list would apply
some DKIM signature of its own, it cannot do so for the RFC5322.From
domain as required by DMARC 4.2.1.

I believe this makes a DMARC failure result inevitable.  In my first few
days of trying DMARC this has been quite apparent from my mails to
@lists.debian.org and @freebsd.org triggering failure reports.

Some recipients like Google Mail recognise those lists and use the
mailing_list policy override.  But this is not the default behaviour of
DMARC and so most other mail receivers who implement it, report a failure.

With many DMARC implementors probably subscribed to this list, I expect
to be receiving some new failure reports shortly :)

Regards,
-- 
Steven Chamberlain
steven at pyro.eu.org


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