Displaying addresses in emails from a Mailman 3 installation
In a list I administer, the From line in an incoming email shows [Poster's Name] via [List Name] <address for posting a reply> . I use Outlook as my client, but at least some other clients behave similarly. However, I have at least one subscriber who uses Mozilla's Thunderbird as his client, and periodically the format changes to something else, most recently to just [List Name <address for posting a reply> . I suspect this occurs from some combination of the way Thunderbird parses the header and the way it populates some kind of address book that makes autofill work, but I'm not sure. Is this a known problem? Is there an easy fix that will be stable? In the past, putting an association in his address book and removing others worked, but it didn't hold and he is frustrated.
On 7/2/25 17:21, Steve Brown via Mailman-users wrote:
In a list I administer, the From line in an incoming email shows [Poster's Name] via [List Name] <address for posting a reply> . I use Outlook as my client, but at least some other clients behave similarly. However, I have at least one subscriber who uses Mozilla's Thunderbird as his client, and periodically the format changes to something else, most recently to just [List Name <address for posting a reply> . I suspect this occurs from some combination of the way Thunderbird parses the header and the way it populates some kind of address book that makes autofill work, but I'm not sure. Is this a known problem? Is there an easy fix that will be stable? In the past, putting an association in his address book and removing others worked, but it didn't hold and he is frustrated.
This From: is the result of DMARC mitigations. The actual From: header in the email is
From: [Poster's Name] via [List Name] <address for posting a reply>
where [Poster's Name] is the first non-empty value from
- the display name in the original From:
- tne display name in the posters member record
- the poster's email address with the domain replaced with
---
How this header is rendered by any particular mail client (MUA) is up to that MUA and not something you can control.
Note however that I use T-bird as my MUA and T-bird displays the From: in your mail from the list as
From Steve Brown via Mailman-users <mailman-users@mailman3.org>
Also, Mailman puts your original From: in a Reply-To: which T-bird displays as
Reply-To Steve Brown <drstephenlbrown@gmail.com>
Depending on your list's settings, the original From: might be in Cc: rather than Reply-To:
And, if the T-bird user really needs to see the poster's name and it's not in any displayed headers, they can always view the source of the message and see the From: there.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
Thanks, Mark. As usual, your reply was rapid and helpful. I infer that you don't see the instability that my subscriber does. Do (can?) email providers passing the posts to the subscriber alter the headers in ways that might lead to that unstable behavior? Or can it occur because of the way T-bird tries to help the user associate display names with email addresses--autofill and address book automation? Do you have those kind of features turned off in your T-bird? Or is it more likely that the subscriber makes some mistakes that get interpreted as needing a change in From displays? Because only one of my subscribers is complaining regularly, it's not very important for me to do anything, but I'm still curious about the origin of this behavior.
On 7/2/25 19:50, Steve Brown via Mailman-users wrote:
Thanks, Mark. As usual, your reply was rapid and helpful. I infer that you don't see the instability that my subscriber does.
I'm pretty sure I don't, but I'm not completely certain I would notice.
Do (can?) email providers passing the posts to the subscriber alter the headers in ways that might lead to that unstable behavior?
It is possible, but I don't think likely that the final mail delivery agent would do this. It's also almost certain that no intermediate MTA is doing it.
Or can it occur because of the way T-bird tries to help the user associate display names with email addresses--autofill and address book automation?
That seems unlikely since those things would be tied to the email address which is always the same list posting address.
Do you have those kind of features turned off in your T-bird? Or is it more likely that the subscriber makes some mistakes that get interpreted as needing a change in From displays? Because only one of my subscribers is complaining regularly, it's not very important for me to do anything, but I'm still curious about the origin of this behavior.
I don't think I have any non-default settings in my T-bird, and I do have address book entries for various lists and I don't see T-bird showing messages From the display names in my address book.
I am curious as to what the complaint is. Does the user feel that something important is missing or is the concern just the inconsistency?
Also, is there any correlation between the inconsistent behavior and what the poster's name is?
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
I may include more info than you really want to know. Here is the gist of the complaint:
"For a while now, my e-mail for this list (but not other lists) just shows "To RADG" from "RADG" with a "CC" showing the actual sender's address. That becomes a PITA when I need to find a post by a particular person, because the e-mail list does not show the CCs in the list, so I need to open each one to see who actually sent it."
This subscriber is not very savvy about email, and doesn't seem to understand fully when I tell him how it works, so if I start talking about headers, that's a PITA, too. He claims:
"RADG is the only list that is afflicted by this, out of 21 that include groups.io, yahoo, google, Lyris, and probably a few I don't recall."
Because some other members, including me, have had problems with unexpected entries in both From and To lines, I suspect that Mailman 3 does the DMARC enough differently than other lists and forums to cause conflicts with the way the MUAs try to help the user autocomplete an address. Most of those problems go away if they put an association of RADG (Risk Analysis Discussion Group) with radg@lists.radg.us in their address book. We chose the "use your own URL" option. The actual server address is deu.mailmanlists.eu; I don't know whether their customization of the MM3 installation might cause some of the problem.
My understanding is that all of the recent posts are missing the poster's name, after behaving as expected for some time. Something must have changed, but what is baffling me. If you have any further ideas, fine, but don't waste a lot of time on this.
Steve
Steve Brown via Mailman-users writes:
"For a while now, my e-mail for this list (but not other lists) just shows "To RADG" from "RADG" with a "CC" showing the actual sender's address.
It's very difficult to figure out what's going on with such an abbreviated description of what he's seeing.
It may be possible to get better results with alterative settings on the list.
In the settings for RADG, under "Alter Messages", what are the settings for "First strip Reply-To", "Reply goes to list", and "Explicit reply-to address"?
Under "DMARC mitigations", what are the settings for "DMARC mitigation action" and "DMARC mitigate unconditionally"?
Because some other members, including me, have had problems with unexpected entries in both From and To lines, I suspect that Mailman 3 does the DMARC enough differently
The only thing I can think of that might allow other lists to have author names for other lists but not for a Mailman list is that the MUAs are parsing email addresses out of the display name (which is a horrible risk, given the flexibility that users have in setting email headers, and especially display names). If there is no email address, then they completely ignore the content of the display name in favor of their preferred display name for the list.
My understanding is that all of the recent posts are missing the poster's name, after behaving as expected for some time. Something must have changed, but what is baffling me. If you have any further ideas, fine, but don't waste a lot of time on this.
MUA "upgrade" seems like as likely an explanation as any. I think if you want to know details what's going on for a particular user, their MUA's support channels are the best bet.
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan
On 7/2/25 22:11, Steve Brown via Mailman-users wrote:
I may include more info than you really want to know. Here is the gist of the complaint:
"For a while now, my e-mail for this list (but not other lists) just shows "To RADG" from "RADG" with a "CC" showing the actual sender's address. That becomes a PITA when I need to find a post by a particular person, because the e-mail list does not show the CCs in the list, so I need to open each one to see who actually sent it."
The user is using T-bird and does not need to scroll through the email list to find a post from a particular user. They should be using quick filter for this. I will send you more detail about this off list as details about the T-bird UI are off topic here.
This subscriber is not very savvy about email, and doesn't seem to understand fully when I tell him how it works, so if I start talking about headers, that's a PITA, too. He claims:
"RADG is the only list that is afflicted by this, out of 21 that include groups.io, yahoo, google, Lyris, and probably a few I don't recall."
Because some other members, including me, have had problems with unexpected entries in both From and To lines, I suspect that Mailman 3 does the DMARC enough differently than other lists and forums to cause conflicts with the way the MUAs try to help the user autocomplete an address. Most of those problems go away if they put an association of RADG (Risk Analysis Discussion Group) with radg@lists.radg.us in their address book. We chose the "use your own URL" option. The actual server address is deu.mailmanlists.eu; I don't know whether their customization of the MM3 installation might cause some of the problem.
My understanding is that all of the recent posts are missing the poster's name, after behaving as expected for some time. Something must have changed, but what is baffling me. If you have any further ideas, fine, but don't waste a lot of time on this.
Mailman, both 2.1 and 3, have been modifying the From: header for DMARC in exactly the same way for years. If anything changed is this regard it is specific to the deu.mailmanlists.eu installation, but I doubt it was Mailman that changed, particularly because you are still seeing the From: as it always was. It is much more likely that the users T-bird changed.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
Hi Steve,
Somebody (maybe me) forgot to send this to the list. Since you mention Mark, I'm sure "to list" was your intention, and I'm going to quote in full as well.
Steve Brown writes:
Thanks, other Steve. I know so little about Alter Messages and DMARC mitigations that I basically left all those settings at their defaults unless I was advised otherwise by the MM3 hosting service (Mailmanlists.net out of Australia).
Internet mail is very complicated. I am somewhat familiar with at least 50 documents describing how it's supposed to work (sometimes multiple editions of the same one!), and I discover new ones that I really ought to learn about several times a year.
First strip Reply-To: nothing; neither Yes nor No is checked
Pretty sure this defaults to "No". To my mind, this should never be done (it means that there may be no way for an MUA to automatically identify and reply to author, and our "anonymous list" style does this anyway so it's not necessary for that purpose), but it is often done by discussion lists that want to keep traffic on-list. I recommend you set it to "No" so you don't have to remember the default.
Reply goes to list: No munging
This is preferred by people who discuss sensitive matters (it reduces accidental distribution of mail intended for specific recipients). Strictly speaking, the Internet standard for the corresponding header's use says that it is to be *set* by the author *only*, but many mailing lists set it to the list to "encourage discussion".
Explicit reply-to address: nothing; box is empty
This only affects anything if "Reply goes to list" is set to explicit.
DMARC mitigation action: Replace From: with list address
This is the recommended setting. "None" is impractical because many recipients will reject a lot of mail, which will be recorded as bounces for those recipients (who are doing nothing wrong). "Wrap" is impractical because there are a number of popular mail clients (Apple Mail, for one) which make it almost impossible to read the mail. And reject and discard mean that those authors can't post to your list at all, but they usually can't affect their email providers' DMARC policies.
DMARC Mitigate unconditionally: Yes
This one you should talk to your subscribers and maybe your provider. "Yes" means that *all* posts will have From changed to the "Steve Brown via a-list@example.net" form. An alternative is to set it to "No", which means that the mailing list checks the policy of the author's domain, and changes From only if the domain has a policy of "reject" or "quarantine".
Advantage:
- Some fraction of the posts would have "From" displayed as the author intended it. Depends on policies of your posters' providers. Could be very large if most are academics posting from departmental addresses, could be very small if most are posting from personal Gmail addresses.
There are three possible downsides:
- People from "strict" domains complain about discrimination.
- Subscribers are confused by multiple formats.
- The list's administrative burden increases because Gmail in its infinite disdain for the rest of the world has decided that it does not apply DMARC to mail received by the rest of the world (its published policy is "none"), but it *does* apply it to mail Gmail -> list -> Gmail. I think the most recent versions of Mailman 3 apply the mitigation action to Gmail implicitly, and if not it's simple to add "^.*@gmail\.com" to the "DMARC addresses" setting. The issue is that other providers may think "that's a great idea", and there's no way to find out they're doing it except that you get a lot of bouncers from subscribers using that provider. So you have to monitor bounces.
If you think it might help to change any of those, I'll try it and then roll back if it causes other problems.
That's your call. I do recommend setting "First strip Reply-To" to "No" to make it explicit. All the others except "DMARC Mitigate unconditionally" are the recommended settings for your purposes.
For "DMARC Mitigate unconditionally", I remember a lot of complaints from AOL and Yahoo! users back in the day about "discrimination", but I imagine people are used to DMARC mitigation by now (and of course popular MUAs try to hide it using associations). I've never seen much confusion from the multiple formats, but some people just value consistency in the user interfaces they use. And the administrative burden is likely to be nil unless you're really compulsive about such things -- you just wait for bounces from a random domain to spike and check for "From a@ran.dom" getting bounced by "subscriber@ran.dom", and add "^.+@ran\.dom" to the "DMARC addresses" list if and when it happens. Really only Gmail and Yahoo! are big enough to do this, and most yahoo.* domains already have a "reject" policy.
I also think that a tweak to the T-bird MUA is a strong suspect. The affected subscriber is an old guy like me and in my experience it is also a PITA for him to deal with Mozilla, his email provider (Breezeline), or any other tech intermediary.
Mark: Thanks for the suggestions on searching T-bird emails. I'm going to refrain from passing them on to my subscriber right now as they would probably seem like another PITA.
I agree on that one, although in the long run he'd probably be a lot happier. Another possibility would be to keep a browser tab open on HyperKitty's RADG page, and search authors there. This should work because DMARC processing takes place after archiving in the builtin pipeline, so HyperKitty should know the author accurately. Of course this is suboptimal, but it may be more straightforward than messing with MUA settings (and it works for all MUAs!)
Regards, Yet another Steve
On Thu, Jul 3, 2025 at 12:06?AM Stephen J. Turnbull <steve@turnbull.jp> wrote:
Steve Brown via Mailman-users writes:
"For a while now, my e-mail for this list (but not other lists) just shows "To RADG" from "RADG" with a "CC" showing the actual sender's address.
It's very difficult to figure out what's going on with such an abbreviated description of what he's seeing.
It may be possible to get better results with alterative settings on the list.
In the settings for RADG, under "Alter Messages", what are the settings for "First strip Reply-To", "Reply goes to list", and "Explicit reply-to address"?
Under "DMARC mitigations", what are the settings for "DMARC mitigation action" and "DMARC mitigate unconditionally"?
Because some other members, including me, have had problems with unexpected entries in both From and To lines, I suspect that Mailman 3 does the DMARC enough differently
The only thing I can think of that might allow other lists to have author names for other lists but not for a Mailman list is that the MUAs are parsing email addresses out of the display name (which is a horrible risk, given the flexibility that users have in setting email headers, and especially display names). If there is no email address, then they completely ignore the content of the display name in favor of their preferred display name for the list.
My understanding is that all of the recent posts are missing the poster's name, after behaving as expected for some time. Something must have changed, but what is baffling me. If you have any further ideas, fine, but don't waste a lot of time on this.
MUA "upgrade" seems like as likely an explanation as any. I think if you want to know details what's going on for a particular user, their MUA's support channels are the best bet.
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan
Yes, I intended to post to the list. I now see that if I use the archives to post (as I'm doing now), I have to use "reply all". On my Outlook, it's the other way around. If I want to reply off-list, I have to click on reply all and then remove the list address. Sorry. I only use the Gmail address for a few limited purposes.
I did set First Strip to a hard no. I' m going to have to think more about the unconditional DMARC. Given what you said, I may well cause more grief than I alleviate. Our list (lists.radg.us) has only about 60 members, but with a lot of different email configurations. Gmail, Yahoo/AOL, Hotmail and similar, academic .edu domains, corporate domains, email offered by ISPs, and personal domains like yours. I use two .us domains, one registered and hosted by TMD and one by Hostinger, because they were relatively cheap. I don't see any apple iCloud, but maybe that's because they use a domain alias.
Many if not most of the subscribers to RADG are not very IT savvy, so I suspect that using the archive for search or posting would also seem like a PITA. But I may suggest it after he cools down.
Thanks again for the help.
Steve B
On 7/4/25 11:08, Steve Brown via Mailman-users wrote:
Yes, I intended to post to the list. I now see that if I use the archives to post (as I'm doing now), I have to use "reply all". On my Outlook, it's the other way around. If I want to reply off-list, I have to click on reply all and then remove the list address. Sorry. I only use the Gmail address for a few limited purposes.
I don't understand. When I reply from HyperKitty, the reply just goes to the list whether I enter the reply in the web UI or "Use email software". There is no "reply all" option and no way to reply to the poster other than using the "Use email software" method and manually adjusting the recipient addresses. Is this not the case with you?
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan
Apologies. I probably replied to Turnbull from Gmail instead of from the archives, i.e. HyperKitty. I almost always use the latter, so just assumed that was how I had managed to send a DM to Turnbull instead of a post to the list. The distinction between Outlook and Gmail still stands.
Steve Brown
Steve Brown writes:
Yes, I intended to post to the list. I now see that if I use the archives to post (as I'm doing now),
As Mark said, you posted via Gmail (first Received header plus lots of GoogleMail internal data).
I don't see any apple iCloud,
Gmail, Yahoo, Hotmail users mostly use the webmail of the provider so their address is a very good clue to the capabilities of their MUAs, but Apple Mail is an app on the iPhone or Mac. You'd have to look at the content of the mail (sometimes there's a User-Agent header, or iPhones often have "sent from my iPhone" as a footer) to know that someone is using Apple Mail, just as you'd need to do a bit of header spelunking to find out that I use the VM application on XEmacs on Mac. I know a fair number of Gmail users who use Apple Mail on Mac rather than Google's webmail, and a very few who have Outlook addresses. Your academic users very likely include a high percentage of Apple Mail users.
"Wrap" is known to have been problematic with iPhones, unclear about Apple Mail on Mac (but it's a good bet given Apple's penchant for reusing Mac code on iOS). Since "Munge From" is now the industry standard for dealing with sites that use DMARC reject policies, it wasn't worth it to check if Apple Mail improved over time.
so I suspect that using the archive for search or posting would also seem like a PITA.
Sure. We have to acknowledge that all of these suggestions are just workarounds for a fundamental issue with current email MUAs (specifically, defaulting to unsigned mail and depending on providers to authenticate).
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan
Thanks again. I feel like I've learned a lot about email since I began administering a MM3 list, but I clearly have only scratched the surface. This thread has added to my understanding and is appreciated. I suppose there is no chance for establishing an industry standard for MUAs, because that would keep the competitors from being able to brag about their superior features.
Steve Brown
participants (3)
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Mark Sapiro -
Stephen J. Turnbull -
Steve Brown