[Mailman-Users] New Problems with AOL & DMARC

Mark Sapiro mark at msapiro.net
Fri Jan 5 22:55:21 EST 2018

On 01/05/2018 07:31 PM, Richard Damon wrote:
> I use Mailman versioon 2.1.25 on a shared host, and in the past couple
> of days, something seems to have changed, as posts from AOL users are no
> longer getting their from address munged like they were a week ago, and
> I am getting massive bounces for DMARC rejection when a poster from AOL
> posts.
> Has something changed with their settings, and is their anything I can
> do about it?

$ dig txt _dmarc.aol.com
_dmarc.aol.com.		3600	IN	TXT	"v=DMARC1; p=reject; pct=100;
rua=mailto:d at rua.agari.com; ruf=mailto:d at ruf.agari.com;"

So, they are still publishing p=reject, and in any case if their policy
changed so dmarc_moderation_action wasn't being applied, the mail
wouldn't bounce for DMARC either.

First, ensure that the list's Privacy options... -> Sender filters ->
dmarc_moderation_action is Mung From.

Assuming it is, if you have access to Mailman's logs, check the 'error'
log for messages like 'DNS lookup for dmarc_moderation_action for list
<listname> not available' which means that

import dns.resolver
from dns.exception import DNSException

(from the dnspython package) failed. Also look for messages containing
DNSException or DMARC.

Check the 'vette' log for messages like
'<listname>: DMARC lookup for user at aol.com (_dmarc.yahoo.com) found
p=reject in _dmarc.yahoo.com. = v=DMARC1; p=reject; pct=100;
rua=mailto:dmarc_y_rua at yahoo.com;'

which would indicate that the lookups are being done.

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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