[Mailman-Users] Massive amounts of bounces after setting munge_from for dmarc compliance

Yasuhito FUTATSUKI futatuki at poem.co.jp
Tue Nov 19 13:08:42 EST 2019


On 2019/11/20 2:27, Andy Cravens wrote:


> I meant to say our default setting for all lists is to set from_is_list to munge_from.  I also realized that some list managers (who’s domain uses DKIM) have added footers to their mailing list so I’ll have to strip the DKIM headers no matter what.  Finally, in the documentation I have found I see two variations for setting REMOVE_DKIM_HEADERS.
> Which one is correct?

I only answer to the last question (I don't know whether your judgement
is appropriate or not).

In Mailman/Defaults.py.in (on 2.1.29, not changed since rev.1655, before 2.1.23):
# Some list posts and mail to the -owner address may contain DomainKey or
# DomainKeys Identified Mail (DKIM) signature headers <http://www.dkim.org/>.
# Various list transformations to the message such as adding a list header or
# footer or scrubbing attachments or even reply-to munging can break these
# signatures.  It is generally felt that these signatures have value, even if
# broken and even if the outgoing message is resigned.  However, some sites
# may wish to remove these headers.  Possible values and meanings are:
# No, 0, False -> do not remove headers.
# Yes, 1, True -> remove headers only if we are munging the from header due
#                 to from_is_list or dmarc_moderation_action.
# 2 -> always remove headers.
# 3 -> always remove, rename and preserve original DKIM headers.

So, both are equivalent.

Yasuhito FUTATSUKI <futatuki at poem.co.jp>

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