Re: [dmarc-ietf] Guidance around constructing an AAR when multiple AR headers are present?

["John Levine" <[e-mail]>]

In article <CAOZAAfOsRrQF2M3NzcB3h2Tc03mtFfG8mOJ0pqU+_cx=[e-mail]> you write:
>Looking at random messages on this list, I've seen anywhere from two to
>five AR headers per message. Locally, with opendkim and opendmarc running,
>there are three locally generated AR headers that get passed to openarc. It
>looks like seeing multiple AR headers is going to be a common occurrence
>for ARC implementations to handle.

When I take a look, I only see one, from ietfa.amsl.com.  If I were
having the list mailed to me, I'd expect to see two, that one plus the
one my system adds.  It is rather peculiar to have multiple headers
with the same service identifier, since section 5 of RFC 7601 says
that you normally delete exsting A-R headers with the same
authserv-id before you add a new one.

On my system, the SMTP daemon calls the spf2, opendkim, and opendmarc
libraries, and then puts all the results in a single A-R header.  For
example, when I look at mail from a list I forward to a gmail account,
I see one A-R header from mx.google.com, one from my system, and maybe
one from the original system.  I think that's more typical.

>Is this a problem the group thinks needs discussion?

Only if there are a lot of MTAs that don't report their results in one
header.

R's,
John