DMARC/DKIM mitigation on maling lists

[Greg Troxel]

Markus Neteler <neteler at osgeo.org> writes:

> On Wed, Nov 8, 2023 at 1:43 PM Greg Troxel <gdt at lexort.com> wrote:
>>
>> This is not really related to dealing with DMARC, but I noticed
>> something in your message.
>>
>> Here are the headers in the messaeg, minus a couple added by my system
>> (spam filtering scores) omitted to reduce noise.
>>
>>   - Your message has a From: of neteler at osgeo.org.
>>   - it was actually sent via google.
>>     * google did not include your client's IP address (that's great)
>>     * google has an X-Google-DKIM-Signature instead of DKIM-Signature
>>       (This is bizarre but not news to me)
>>     * google's faux DKIM header is from 1e100.net
>>       (also odd but not news)
>>   - osgeo.org applied a dkim signature from osgeo.org to the list
>>     message
>
> Would changing anything in this regard help?
> https://wiki.osgeo.org/wiki/SAC:Message_Submission_Agent

Yes, the right thing to do is to send all mail with From: of osgeo
through osgeo's outgoing server.

> I wonder how to make use of this new SAC MUA service with Gmail (which
> many will use) rather than Thunderbird.

gmail is a mail server, not a generic mail client.  In addition, it has
a webmail interface that is, as far as I know, bound to that service.

People will need to use some kind of "Mail User Agent" configured to the
osgeo MSA.

It is somewhat surprising to me that gmail doesn't publish a DMARC
record and people can still inject messages elsewhere with a From: of
gmail.  You can't do this with yahoo.com, for example, and have them be
delivered.  So there is no ability to send @yahoo.com mail with gmail.
Basically one can no longer choose to use "gmail for all mail", unless
all of your outgoing mail has your gmail address in it.