Yahoo DMARC Mailing List Problem and Solution

On April 6, 2014, Yahoo implemented the DMARC anti-spam solution for their subscribers, which causes problems for their subscribers participating in mailing lists.

The Yahoo DMARC changes causes other ISP’s, to reject email from your mailing list, when sent by Yahoo subscribers. These ISP’s include Gmail, Hotmail, Yahoo and Comcast, so it’s a big problem because many of your subscribers will not get messages from Yahoo people.

By rejecting the email at Gmail, Hotmail, Yahoo and Comcast, etc. they also send back a bounce message which can cause your subscribers at Gmail, Hotmail, Yahoo and Comcast to be removed.

So in addition to Gmail, Hotmail, Yahoo and Comcast people not getting the message, they also run the risk of being removed from the list. Even though Yahoo is causing the problem, not Gmail, Hotmail or Comcast.

Mail-List has made a change in our system to accommodate Yahoo subscribers, and any other ISP’s that choose to adapt DMARC.

DMARC flowchart

The change is to add your mailing list address into the From header of messages from Yahoo subscribers. In addition, the first line of the body of those messages will show the Yahoo person’s name and email address to clarify who the message is from.

The mailing list will function as before. If it was set up to Reply To List, replies to Yahoo subscribers will continue to go to the list. If your list is set up to Reply To Individual, a reply will continue to go that person, while a Reply All will continue to go to the list.

We are doing three things to emails from subscribers from Yahoo and other DMARC enabled ISP’s.

  1. Putting their name and email address (with at instead of @), in the From Header.
  2. Also putting the list email address, with an @ symbol and in brackets to signify that it’s the official email address
  3. Putting a line at the top of the message to clarify the sender’s name and email address

Example of email from Yahoo subscribers with Reply To List option


Example of email from Yahoo subscribers with Reply To Sender option


Because the official address in the From header is now our domain (or your domain if you choose), the ISP’s do not ask Yahoo what to do about the incoming email and it is accepted and delivered to the subscribers inbox.

Problem solved.

If your mailing list provider is not able to accommodate these changes, you can transfer your list to Mail-List in a couple of hours. If you have, or can get your historical email archives in an MBOX format, we can import those into our searchable web archive feature.

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