I have set up Postfix to DKIM sign outgoing mails from GNU Mailman 3.2.0a1 which validates nicely ("dkim=pass (signature was verified)"), but DMARC fails ("dmarc=fail action=none") on the recipient end, probably because the "header.from=gmail.com;" (or similar) which means that DKIM d= will not match.
According to dmarc.org*) "Mailing lists usually do not take authorship of the emails they relay" so I should "consider to apply specific rules for emails coming from mailing lists". Also according to dmarc.org*) Mailman (Mailman 2 that is, and I presume Mailman 3 does too) "include features to interoperate with DMARC senders".
I assume that the dmarc mitigations list settings in Mailman is for incoming messages, but how do I set Mailman to cope with this on outgoing messages?
Note: I have more than one list domain in Mailman 3.
*) https://dmarc.org/wiki/FAQ#Is_there_special_handling_required_to_receive_DMA...
/Henrik