"to" Headers for Non-Anonymous lists
Hello,
At the request of a list owner, we changed the settings on a list to "Anonymous = No" so that list members could see who a message was coming from.
It seems a side effect of the setting is that users are now using "reply-to" and some messages are going out to the list addressed in the manner below.
"Last Name, First Name via list-name <list-name@caltech.edu>"
The list owner feels this is confusing and some members may inadvertently email the list when they intend to email the individual.
I understand this is likely a client side caching issue since most email clients create an index of contacts based on previously received emails.
Aside from reverting back to "Anonymous = Yes", is there any setting we can change at the list level to force the "to" field to persist as the list email address?
Thanks in advance for your help.
Dan Caballero Systems Administrator Academic Computing Solutions IMSS - Caltech https://imss.caltech.edu
On 6/9/25 14:23, Dan Caballero wrote:
Hello,
At the request of a list owner, we changed the settings on a list to "Anonymous = No" so that list members could see who a message was coming from.
It seems a side effect of the setting is that users are now using "reply-to" and some messages are going out to the list addressed in the manner below.
"Last Name, First Name via list-name <list-name@caltech.edu>"
This is a consequence of DMARC mitigations.
The list owner feels this is confusing and some members may inadvertently email the list when they intend to email the individual.
When the From is munged in that way for DMARC the orikinal From is put in Reply-To: or perhaps Cc: depending on other settings. See https://gitlab.com/mailman/mailman/-/blob/master/src/mailman/handlers/dmarc.... for details of this process and its goals.
Assuming your list's Reply goes to list setting is No Munging The original From: should be in Reply-To: of the delivered.
It appears that the messages that are sent
To: Last Name, First Name via list-name <list-name@caltech.edu>
are sent by an MUA that is ignoring Reply-To: and replying to From:.
I understand this is likely a client side caching issue since most email clients create an index of contacts based on previously received emails.
Aside from reverting back to "Anonymous = Yes", is there any setting we can change at the list level to force the "to" field to persist as the list email address?
Do you mean you want the From: in delivered messages to be the original poster's From: so that replies to the From: go to the OP. You can accomplish this by setting DMARC mitigation action to No DMARC mitigations, however this will ensure that any mail whose From: domain publishes a DMARC policy of quarantine or reject will most likely be bounced by all large ESPs.
We do are best to ensure that a simple reply to a message to which DMARC mitigations are applied will go to the poster unless the Reply goes to list setting says otherwise.
But I am confused as to your goal. Previously when the list was anonymous, all replies went to the list. Maybe your goal is to have list replies be addressed to <list-name@caltech.edu> rather than Last Name, First Name via list-name <list-name@caltech.edu>. If that is the goal, you could try setting Reply goes to list setting to Reply goes to list. That will set a Reply-To: list's short description <list-name@caltech.edu>. That may be what you want as long as the responder's MUA honors Reply-To: over From:
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
But I am confused as to your goal. Previously when the list was anonymous, all replies went to the list. Maybe your goal is to have list replies be addressed to <list-name@caltech.edu> rather than Last Name, First Name via list-name <list-name@caltech.edu>. If that is the goal, you could try setting Reply goes to list setting to Reply goes to list. That will set a Reply-To: list's short description <list-name@caltech.edu>. That may be what you want as long as the responder's MUA honors Reply-To: over From:
Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
Thanks. I had forgot to mention that we did also configure the DMARC mitigation to show the sender's email. You're correct about us looking to set the "reply-to" to the list address instead of the sender.
I've done some testing and this is close to what we need. However, I seem to be having an issue with the option for "Explicit Reply-to set; no Cc added". The messages are still including a Cc field with the sender's email. Is there another setting that affects the Cc field?
Thanks again.
On 6/10/25 09:40, Dan Caballero wrote:
I've done some testing and this is close to what we need. However, I seem to be having an issue with the option for "Explicit Reply-to set; no Cc added". The messages are still including a Cc field with the sender's email. Is there another setting that affects the Cc field?
The difference between "Explicit Reply-to header set" and "Explicit Reply-to set; no Cc added" only affects lists with Personalize = Full. For those cases, the To: in delivered posts is replaced with the recipient's address which means in some cases, the list's posting address is not exposed so we put it in Cc: unless Reply goes to list is "Explicit Reply-to set; no Cc added". This setting is intended for announce type lists where members normally do not post to the list.
If DMARC mitigations are applied and Reply goes to list is anything other than No Munging, the original From: will always be added to Cc:. There is no setting to avoid this. This is so reply-all will include the original sender.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
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