DMARC and Listserves (Gmail 30Apr2025 edition)
Traditionally, listserves have kept the author's email address in the From header, while delivering the email from the listserve's servers to the subscribers of the mailing list.
The DMARC specification ignores tradition, and allows ISP's to specify which servers are the only servers that can send out that ISP's email.
Yahoo was the first ISP to turn on the DMARC protocol. They do so via a DNS record that looks like this.
v=DMARC1; p=reject; pct=100; rua=mailto:[email protected]; ruf=mailto:[email protected];
Which says to reject any messages from a Yahoo email address, that does not come from its IP addresses.
Mail-List.com will look up the current DMARC policy, and alter the From header if the policy is quarantine or reject.
See https://help.mail-list.com/m/59124/l/946163-dmarc-how-mail-list-com-handles-dmarc-reject-settings
Today 30Apr2025, Gmail says their DMARC policy is none.
v=DMARC1; p=none; sp=quarantine; rua=mailto:[email protected]
Per https://mxtoolbox.com/SuperTool.aspx?action=mx%3agmail.com&run=toolpage#
dig _dmarc.gmail.com txt
Says the same thing
_dmarc.gmail.com. 472 IN TXT "v=DMARC1; p=none; sp=quarantine; rua=mailto:[email protected]"
And yet Gmail people are complaining that emails from other subscribers that also happen to use gmail are going into spam.
They show me this
From: Joh Doe <[email protected]>
Subject: [xxxxx] Notes - Monday April 28th Rehearsal
SPF: PASS with IP 204.236.130.174 Learn more
DKIM: 'PASS' with domain mail-list.com Learn more
DMARC: 'FAIL' Learn more
Which makes it appear that wrong DMARC pushed it into the Spam folder.
In summary, listserve email from a fellow gmail user, will go to spam for all gmail subscribers on the listserve. Gmail is making things worse.
If Gmail had announced via DNS, that they were enforcing quarantine, then Mail-List.com would have made an exception to tradition, and altered the From: header to meet their criteria. In real time.
I have sent an email on 28Apr2025 to [email protected] asking them why the discrepancy, but have not heard back.