Re: [dmarc-ietf] ARC, DMARCbis WGLC

On Tue, Apr 2, 2024 at 11:58 AM Murray S. Kucherawy <superuser@gmail.com>
wrote:

> On Tue, Apr 2, 2024 at 8:49 AM John Levine <johnl@taugh.com> wrote:
>
>> It appears that Murray S. Kucherawy  <superuser@gmail.com> said:
>> >Can you give an example, even if only a hypothetical one?
>>
>> I'm not Emmanuel but people at large mail systems have told me that
>> the biggest value of ARC is to deal with mailing lists that do lousy
>> spam filtering. Lists often let anything through that has the address
>> of a subscriber on the From: line. Mail systems see legit lists that
>> gush spam when some bot starts sending mail to the list with fake
>> subscriber addresses, because the bot herder is using address pairs
>> from stolen address books.
>>
>> While we all know the reasons that you don't want to enforce DMARC on
>> the mail coming out of a mailing list, it makes a lot more sense to
>> enforce it on mail going into a list. You can use ARC to look back and
>> see if the mail was aligned on the way in and if not treat it as spam.
>>
>
> I think details about the technique to which you're alluding, especially
> with real world examples, anecdotes, or other data, would be really
> valuable to publish somewhere, be that in this document or elsewhere.  Even
> just a paragraph that explains what ARC brings that we didn't have before,
> that can be used to mitigate DMARC damage, would be a step in the right
> direction.
>
> The ARC usage document appears to have been parked and expired, so that
> advice doesn't seem to exist anywhere now.  Is the plan to revive that, now
> that we appear to have at least one source of experience?
>

At M3AAWG a month ago, a couple of major mailboxes agreed to share their
experience (and success) with ARC to this list. It is apparently making a
significant difference for their systems. Getting that data public is still
slow moving.

>
> -MSK, p11g
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Re: [dmarc-ietf] ARC, DMARCbis WGLC - Issue 144 Mention of ARC in DMARCbis