[Mailman-Users] DMARC victim example?

[Richard Damon]

On 4/13/14, 6:22 PM, Peter Shute wrote:
> We just had a list member disabled. Is this likely to be caused by the DMARC problem? Here's the header from the attachment in the bounce action notification email:
>
> <xxxxx.xxx at gmail.com> (expanded from <xxxxx at xxxxx.com.au>): host
>     gmail-smtp-in.l.google.com[2607:f8b0:400e:c03::1b] said: 550-5.7.1
>     [2400:8900::f03c:91ff:fedb:b1ff      12] Our system has detected that
>     550-5.7.1 this message is likely unsolicited mail. To reduce the amount of
>     spam 550-5.7.1 sent to Gmail, this message has been blocked. Please visit
>     550-5.7.1 http://support.google.com/mail/bin/answer.py?hl=en&answer=188131
>     for 550 5.7.1 more information. cb4si7487232pbc.409 - gsmtp (in reply to
>     end of DATA command)
>
> I had a look back through a month or so of these notifications, and don't see any others mentioning spam. I'd expect the occasional list message to be detected as spam, but not for 5 days in a row.
>
> But we must have dozens of gmail members, and this is the only one to get disabled. Makes me think this might not be related to DMARC.
>
> We don't get many disabled like this, maybe one a week, and I rarely look at the reasons given.
>
> We've reenabled him for now, so we'll see if it happens again. We've moderated all the yahoo members.
>
> Peter Shute
My guess on how this works is that when you deliver to Gmail, one
message will actually have many recipients, and you will get just a
single rejection, which will be charged to the first person on the list
by mailman. How they are grouped is likely a function of the full
subscriber database, so some might get hit by a few, then someone
(un)subscribes, changing who will be charged with the "problem" Whoever
is "first" in the list of messages going to Gmail, is much less apt to
be moved, so the most likely to get kicked off.

-- 
Richard Damon