On 2/17/23 13:39, denise.mcgeachy--- via Mailman-users wrote:
Hi all - new to this forum but am trying to work out a similar issue raised by a list member's IT department. I'm a bit out of my depth here and hoping you all can help.
They have recommended:
- When the mailing list relay an email from a member of the list to other members, the email from address should be the mailing list and not the user sending the original email. For example: list-name@mydomain.ca (on behalf of Sally Brown)
- The mailing list should not modify the original email and thus breaking the DKIM signature
I have clicked the DMARC mitigation unconditionally option which seems to solve the second point but haven't managed to have it sent by the list name but not as suggested in the first point. I either get "my email via list@mylist.ca" or list@mylist.ca" Is anyone aware of a setting to do this?
Those two points are contradictory. You can't do both. Not modifying the message in ways that break DKIM requires no content filtering, no addition of list headers or footers and no munging of From: or Reply-To: headers. Normally the list will make some modification that will break DKIM signatures.
If you set DMARC mitigation action to Replace From: with list address, and set DMARC Mitigate unconditionally, that should address the first point and individual messages from the list will be From the list and that's all you should need. For example, the message to which I'm replying is
From: denise.mcgeachy--- via Mailman-users <mailman-users@mailman3.org>
While this is not identical to the format you quote, the address is the list's address which is the important thing.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan