[Mailman-Users] Striping out original DKIM header

[Andrew Hodgson]

Syafril Hermansyah [syafril at dutaint.co.id] wrote:

>My list has been run smoothly so far, but I got complaint from list
>member who use yahoo.com family domain, all of their own posting goes to
>to spam folder.

>I suspect this is because mailman not stripe out original DKIM header so
>that the DKIM verification going bad,

[...]

>It does pass DKIM for domain python.org but not pass (BAD) for my own
>domain (my domain has DKIM key).
>This is logically correct since DKIM also sign for content of the
>message and since Mailman alter the content I think she should remove
>original DKIM header.

Simply add the following to mm_cfg.py:

REMOVE_DKIM_HEADERS = Yes

Taken from defaults.py:

# 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 by setting this to Yes.
REMOVE_DKIM_HEADERS = No

Note that there is various discussions around this topic, I had a similar issue with Yahoo, what I ended up doing was signing the messages leaving Mailman using the MTA, and not stripping any DKIM header.  This works fine now and Yahoo subscribers are receiving mail.

Thanks.
Andrew.