Thanks Christian, Mark, & Stephen.
I guess this is a non-issue after all.
I've noticed that all recent posts don't have poster's address in the Reply-To:, but is in the cc: field. I've made sure all members are set to No-dupes.
It is a reply_goes_to_list = this list using Mailman 2.1.23.
Mark Sapiro wrote at 03:36 PM 3/27/2022:
On 3/27/22 12:02, Stephen J. Turnbull wrote:
Getting rid of the poster address in Reply-To requires patching the code. We are not going to change this in Mailman 2, for sure. The general sense of the developers is that it's a bad idea to completely remove the poster's address, and they can work around with no-dupes, so we probably will not change it in Mailman 3 either.
We actually try to ensure that both reply and reply-all to a message with a munged From: do the same thing as they would without From: munging. See <https://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/Mailman/...> To this end if the lists reply_goes_to_list setting is This list or Explicit Address The Poster's address is added to Cc:, and not to Reply-To:.
So the bottom line here is if you have reply_goes_to_list set to This list and the poster's address ends up in Reply-To:, either the poster's address is in Reply-To: in the incoming mail and first_strip_reply_to is No, or more likely, dreamhost's Mailman version is older than 2.1.19 and doesn't have this fix <https://bugs.launchpad.net/mailman/+bug/1407098>.
Note that 2.1.19 was released over 7 years ago.