[Mailman-Users] cause of bounces

Mark Sapiro mark at msapiro.net
Tue Oct 10 22:55:06 EDT 2017

On 10/10/2017 03:20 PM, paul at tokyoprogressive.org wrote:
> A few are unclear, such as RESTARTING Mailman. How does one restart it? I use Cpanel and do not know the inner workings.
> Which do you think it the best of the suggestions? I already have content filtering set to off to allow attachments. And there is currently only a footer that says:

If your cPanel is reasonably up to date, you have Mailman 2.1.23 or
2.1.14. This what you want is in the list admin UI on the Privacy
options... -> Sender filters page set

dmarc_moderation_action = Munge From
dmarc_quarantine_moderation_action = Yes

and if it exists

dmarc_none_moderation_action = No

These are the settings referred to in the last paragraph of item 1) at
<https://wiki.list.org/x/17891458> and described in more detal it the
linked DMARC page at <https://wiki.list.org/DEV/DMARC>.

> it says  "List subscribers with email accounts on servers that perform DMARC checks, such as Gmail, Hotmail (Outlook.com <http://outlook.com/>), Comcast or Yahoo itself, will reject the original message and respond back to the list with automated DMARC error messages"……. making it seem that all of these providers are no-nos.
> But later it says "So users of Gmail, Hotmail and other DMARC-enabled providers will not only fail to receive messages sent to the mailing list by Yahoo users, but will flood the list with bounce messages, risking to be bounced off the list themselves”.
> This sentence seems to imply that it is YAHOO users who should switch. But the previous quote implies people with all of those providers should switch.
> Can you give me your opinion. Is it Yahoo that is breaking mailing lists, or is it Yahoo, Gmail and Hotmail?

The issue is twofold. Mail which will be bounced is mail From:
yahoo.com, aol.com and any other domain that publishes a DMARC policy of
reject. Initially, the only freemail provider to do this was Yahoo, but
AOL soon followed. Currently both Gmail and Hotmail and also Comcast
publish DMARC p=none, so mail From: those domains should not be bounced
for DMARC policy reasons, BUT all 5 of those ISPs and many others honor
DMARC which means they will all reject mail that fails DMARC from Yahoo
and AOL and any other domain that publishes DMARC p=reject.

So no, neither quote implies Gmail or Hotmail user's need to switch. It
only says that those users won't receive unmitigated posts sent by Yahoo
users. and that those ISP's and others will bounce the Yahoo mail.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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