Mailman updated to avoid DMARC problem
In recent days, Yahoo and AOL made technical changes that prevented their own users from sending messages to most mailing lists. (That’s a simplified summary; your favorite search engine will show the gory details if you search for “Yahoo DMARC mailing lists”.)
If you use the Mailman software to run discussion lists, like many of our customers, this is a problem. To fix it, the authors of the Mailman software are making a new version to work around the Yahoo and AOL change.
That new version hasn’t been officially released yet, but we think this is so important that we’ve upgraded our installed copy of Mailman to a “pre-release” version of the fixed software.
Yahoo and AOL users should now be able to send to our customers’ Mailman lists without trouble.
For those interested in the technical details: We’ve switched to Mailman version 2.1.18rc2 plus this bug fix patch, with the DMARC moderation action set to “munge” the from address as the default for all lists.
This version passes all our standard Mailman tests, and we’re confident that it’s an improvement. We’ll upgrade to the official final version 2.1.18 soon after it’s released, of course.
Update April 26: We’ve upgraded to Mailman version 2.1.18rc3.
Update May 8: We’ve upgraded to the final Mailman release 2.1.18-1.