DKIM and DMARC failing for Google/Yahoo users on your list

Hi Charles,

I've been a member of this list for ... somewhere near a decade now.

For a few years, I've had a number of messages marked as spam by GMail, and
in some cases, being entirely refused by Google's servers (Yahoo's quite
strict p=reject dmarc/spf policy when any of their mail users sends mail to
a list.)

To this end, you can reference this snippet of a bounce message from your
ezmlm server to me indicating it couldn't deliver some messages:

"
[email protected]
Tue, Aug 28, 5:49 AM
 to me

Hi! This is the ezmlm program. I'm managing the [email protected]
mailing list.

I'm working for my owner, who can be reached at
[email protected].

Messages to you from the getmail mailing list seem to have been bouncing.
I've attached a copy of the first bounce message I received.

[some extra mundanity elided]

Here are the message numbers:

   6488
   6487

--- Enclosed is a copy of the bounce message I received.

Return-Path: <>
Received: (qmail 22862 invoked for bounce); 13 Aug 2018 21:45:43 -0000
Date: 13 Aug 2018 21:45:43 -0000
From: [email protected]
To: [email protected]
Subject: failure notice

Hi. This is the qmail-send program at pyropus.ca.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

<[email protected]>:
108.177.103.27 failed after I sent the message.
Remote host said: 550-5.7.1 Unauthenticated email from rocketmail.com is
not accepted due to
550-5.7.1 domain's DMARC policy. Please contact the administrator of
550-5.7.1 rocketmail.com domain if this was a legitimate mail. Please visit
550-5.7.1  https://support.google.com/mail/answer/2451690 to learn about the
550 5.7.1 DMARC initiative. g62-v6si11994872oif.321 - gsmtp
"
Due to this, I've had to place mailinglists into a filter that 'never sends
to spam', which implies my hope that the list itself never gets actual spam
that should be blocked, because if it DOES get spammed, I cannot, without
knowing the details behind Google's "spam" classification (who nobody but
them), in good faith mark the messages as "spam" manually as it might cause
further delivery failures for your domain at Google in the future.

I've worked in a managed web-hosting datacenter, and saw so many times
where Google had entirely blacklisted a customer's server IP, due to
forwarding messages to the customer themselves at Gmail, and the customer
then had marked a forwarded message as spam.  Since I don't know if Google
treats mailinglists differently, I must assume that my manual "spam" click
will affect your server's deliverability thereafter.

However, I wonder if perhaps a small change on your end might not help the
issue..

http://lists.dmarc.org/pipermail/dmarc-discuss/2014-August/003069.html
indicates that ezmlm-idx has patches, but I don't see the -idx moniker on
your ezmlm install, so I propose changing the list manager from what
appears to be ezmlm-0.53 to the more updated -idx variant.

Back when I first started using Getmail, I ran a local
net-qmail+ezmlm-idx+vpopmail installation on my bedroom server, and if you
worry that -idx won't work well, I assure you it did then, and have very
high confidence that it will now.

Thanks for your interest in fixing this problem,

Mike