- Mailman-users - lists.mailman3.org

An introduction to Dynamic Sublists (Conversations) - GSoC 2026
by Archie Singh May 1, 2026

May 1, 2026

Hello everyone I am Archie Singh, a Computer Science Engineering student from the Indian Institute of Technology (IIT), Jodhpur. I am elated to announce that I have been selected as a contributor for Google Summer of Code 2026. I will be implementing Dynamic Sublists into the Mailman 3 Suite this summer. Mailing lists are essential for broadcasting, but high-traffic lists frequently fill up inboxes with replies to specific topics users might not be interested in. This project transforms this rigid broadcast model into an opt-in thread model. The goal is to ensure only the root email of a new topic is broadcast to the main mailing list. If the topic diverges into a specific task or discussion, subsequent replies will route strictly to a child list, delivering mail only to users who have explicitly opted in via email commands. I would love to hear your thoughts. Would an opt-in thread model be useful for specific topics? How do you folks handle email overloads? I will be updating more on: Blog <https://hashnode.com/@archiesingh> Thank you Regards Archie Singh

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Introducing my GSoC 2026 project: Domain Administration in Postorius
by Khushal A May 1, 2026

May 1, 2026

Hi everyone, I'm Khushal, a final year Computer Science student from R V College of Engineering, India. I've been selected for Google Summer of Code 2026 with GNU Mailman project. I'll be working on Domain Administration in Postorius. Right now, Mailman has roles like site admins and list owners, but domain level management is still limited. The idea of this project is to make the domain owner role actually usable. A domain owner should be able to create lists in their domain, manage those lists with the same permissions as a list owner, and edit domain level settings for their domain. For example, if multiple domains are hosted on the same Mailman instance, each domain can be managed independently by its own owner without needing full admin access. Would love to hear how you currently manage domains and if there are any pain points. I’ll be sharing updates here: https://hashnode.com/@a-khushal Thanks, Khushal (a-khushal)

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How to build docs and how to contribute documentation
by mailman26＠xse.com May 1, 2026

May 1, 2026

I have mailman 3 working with sendmail (FreeBSD system) and when I was setting this up I found the "Sendmail" section of the docs to be somewhat thin: https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.h… It points to two different versions of the mailertable hack: https://gist.github.com/Maeglin73/72eb5b1e4ee66a383c2aa454726be9a5 https://gitlab.com/mailman/mailman/-/work_items/307#note_632495542 I got a version of this to work but was not satisfied because it required hacking either mailman or sendmail config to cleanup the domain in the recipient address. Eventually I realized that "mailman inject" could be use in very similar way to how mailman 2 lists work with sendmail (alias pipe to a command). This provides a path to submit messages without using LMTP. First, how does one build the mailman 3 documentation? I am mildly experienced with sphinx so the actual changes are not an issue. But I was only able to build mailman-suite-doc documentation; it wasn't obvious to me now to build docs for mailman core (let alone an of the other pages I find on docs.mailman3.org) Next, how are code and documentation contributions submitted for consideration? I'm a lot more familiar with github than gitlab and know how to fork but it didn't look like I would be able to submit a pull request. Craig

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captcha for subscription and account registration forms
by Johannes Rohr May 1, 2026

May 1, 2026

Dear all, in mailman installed in venv is there really no canonical way of integrating a captcha into postorius' subscription and account registration forms? We are increasingly getting hammered by spambots, and a captcha would seem like a simple and effective solution. Thanks for any suggestions! Johannes

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Mass subscribe operation fails with http error
by b.watts＠ucl.ac.uk April 30, 2026

April 30, 2026

Hi, We have a mailing list where the admin has configured a custom template: [list:user:action:invite] When inviting a user using Mass Subscribe, the operation fails with the error: HTTP Error 400: ('Connection aborted.', ConnectionResetError(104, 'Connection reset by peer')) I have reviewed similar threads, including: https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/thread/… I have updated the config in: /etc/mailman3/settings.py to contain: POSTORIUS_TEMPLATE_BASE_URL = 'https://mailinglists.ucl.ac.uk' After adding that item, I've recreated the template and resubmitted the subscribe. But still get the same error. What could I try next? Regards, Brian Senior Systems Administrator, UCL ISD

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How to configure an announce-only list?
by mailman26＠xse.com April 29, 2026

April 29, 2026

I want to create a mailing list that is used for announcements only. I'd like attempts to post to be rejected with a notification. I was able to set the list pw and verify it works with the Approved header using this reference: https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/rules/docs… I find that if both: Default action to take when a member posts to the list Default action to take when a non-member posts to the list are set to "reject (with notification)", the approved header is ignored and messages are always rejected (posted via "mailman inject") Would it be bad to test the approved header before rejecting a message? Essentially always accept a message with a valid approved header? Is there another way for me to achieve this? On another front, I'm unable to have messages posted via "mailman inject" use postorius created list templates. Would it be difficult to add this functionality?

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dmarc_mitigate_unconditionally vs. mitigate_owner_mail
by Lichtinger, Bernhard April 28, 2026

April 28, 2026

Hello, We stumbled over an interesting problem with latest mailman-core from git if the setup matches some criteria: 1. Config of mailman3: mitigate_owner_mail = no (default) 2. Config of list: dmarc_mitigate_unconditionally = yes AND dmarc_mitigate_action = munge_from 3. Owner of list has an automatic out-of-office reply enabled 4. Owner is allowed to post on list 5. Somebody writes to list-owner@mailman ==> Result: Somebody's mail gets treated with munged_from and the owner's out-of-office reply is sent to the list and distributed to all members. I expected that with "mitigate_owner_mail = no" there would be no munge_from for mails to list-owner@mailman. But in the end "dmarc_mitigate_unconditionally = yes" has higher precedence than "mitigate_owner_mail = no" in handlers/dmarc.py. I am not sure if this is a bug or a feature ;) As a quick workaround to prevent out-of-office replies going to the list, we configured our postfix to add a "precedence: list" header to all mails sent to an -owner address to prevent to trigger an auto reply. We set dmarc_mitigate_unconditionally = yes AND dmarc_mitigate_action = munge_from to prevent confusing our users if the mails from the list look different dependent on the sender's DMARC policy. And we also don't have to worry about adding tags to the subject or adding headers/footers. With munge_from our DKIM signature is always aligned with the header from domain and gmail, yahoo, etc. are happy. While thinking about our situation I came up with some more thoughts: With mitigate_owner_mail = yes and munge_from is the list posting address really a good choice for the new header from address? Not only auto replies but also owners who click "reply all" without thinking will post to the list. But using the list-owner as new header from would also have some drawbacks, e.g. the possibility of an endless loop of auto replies. Adding the "precedence: list" header also to mails sent to the list-owner might prevent this in most cases at least. But this feels like putting more tape on the problem. In my opinion the least bad solution would be to give "mitigate_owner_mail = no" higher precedence than "dmarc_mitigate_unconditionally = yes". Then the site admin can overrule the list admin. Or will this break other uses cases I did not think about? Regards, Bernhard

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Re: Incorrect error log message in OutgoingRunner._dispose()
by Mark Sapiro April 26, 2026

April 26, 2026

On 4/26/26 10:42 AM, Craig Leres wrote: > On 4/26/26 06:52, Mark Sapiro wrote: >> >> Did you by chance run import21 as root or another non-mailman user >> resulting in template files unreadable by Mailman? > > Yes and no. I ran it as a user in group mailman; the template files are > owned by the user but are group mailman read/write... Then those templates in Mailman's var/templates/LIST-ID/LC/ should be used for the list for that language as long as they are readable and not overridden by a Postorius template or other URI for the list in the template table in the database. Was there anything in mailman.log prior to your defining a Postorius template indicating why they weren't used? >>> Apr 25 12:32:22 2026 (82977) Cannot connect to SMTP server >>> 127.0.0.1 on port 25 >> >> This is a well known issue. See <https://gitlab.com/mailman/mailman/-/ >> work_items/582> and related issues referenced therein. > ... > What really bothers me about the error message is that it's reporting a > SMTP connection failure when what really happened was a HTTP connection > failure. That is all part of the above referenced issues. It is a bug and should be fixed but hasn't been yet. It is caused by the low level socket error upon trying to fetch the template, ultimately being caught by the try/except in outgoing runner's sending of the message. >>> I'm using the default webservice port (8001) so I would not expect >>> anything to ever be listening on 8000. >> >> The default web service port (Postorius and HyperKitty) is 8000. Port >> 8001 is Mailman core's rest api. > > Ah. I never noticed anything telling me the apache config needed to also > listen on 8000. It's also confusing to me to call the rest api port the > "web service port" (Also, I'm not running hyperkitty.) Apache doesn't listen on port 8000. The WSGI server (uWsgi or Gunicorn or ...) listens on port 8000 and Apache listens on ports 80 and 443 as normal and proxies the mailman requests to port 8000. > Ok, I added apache config to handle 127:0.0.1:8000 and that solves the > "SMTP" (HTTP) connection error and cpu bound runner. I don't know what you did, but see <https://docs.mailman3.org/en/latest/install/virtualenv.html#apache-configur…> for how Apache should proxy to port 8000. > I still can't get templates to work but I'll debug further and ask for > help later if I still can't get it to work. Do you have a WSGI server running and listening on port 8000? See <https://docs.mailman3.org/en/latest/install/virtualenv.html#setting-up-a-ws…>. You need this for Postorius as Postorius is a Django project and Django is a WSGI application. -- Mark Sapiro <mark(a)msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan

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Incorrect error log message in OutgoingRunner._dispose()
by mailman26＠xse.com April 26, 2026

April 26, 2026

I'm trying to bring up mailman 3 in a spare vm prior to upgrading a production system from mailman 2. One feature the existing mailman 2 lists uses that I can't get working with mailman 3 are templates. After using "mailman import21" I found files with names such as list:member:regular:footer.txt in the list tree. However they were ignored so I removed them I tried tried creating a template using the web postorius gui. When a message is injected, I see an error log from the out runner: Apr 25 12:32:22 2026 (82977) Cannot connect to SMTP server 127.0.0.1 on port 25 Following the error message, the out runner goes cpu bound, creating and deleting queue files in queue/out with .pck and .bak extensions, very quickly. I updated the code to print the exception and it tells a completely different story: Apr 25 12:38:15 2026 (83339) Cannot connect to SMTP server 127.0.0.1 on port 25 (HTTPConnectionPool(host='localhost', port=8000): Max retries exceeded with url: /api/templates/list/test.example.com/list:member:regular:footer (Caused by NewConnectionError("HTTPConnection(host='localhost', port=8000): Failed to establish a new connection: [Errno 61] Connection refused"))) I'm using the default webservice port (8001) so I would not expect anything to ever be listening on 8000. When I stop the runners, the problematic queue file is moved to the shunt queue. Here's what I changed to get the exception detail: mm 287 # pwd /usr/local/lib/python3.11/site-packages/mailman/runners mm 288 # diff -c /var/tmp/outgoing.py outgoing.py *** /var/tmp/outgoing.py Thu Apr 23 14:26:22 2026 --- outgoing.py Sat Apr 25 12:34:33 2026 *************** *** 110,116 **** self._func, msg.get('message-id', 'n/a'))) self._func(mlist, msg, msgdata) self._logged = False ! except socket.error: # There was a problem connecting to the SMTP server. Log this # once, but crank up our sleep time so we don't fill the error # log. --- 110,116 ---- self._func, msg.get('message-id', 'n/a'))) self._func(mlist, msg, msgdata) self._logged = False ! except socket.error as e: # There was a problem connecting to the SMTP server. Log this # once, but crank up our sleep time so we don't fill the error # log. *************** *** 118,125 **** if port == 0: port = 'smtp' # Log this just once. if not self._logged: ! log.error('Cannot connect to SMTP server %s on port %s', ! config.mta.smtp_host, port) self._logged = True return True except SomeRecipientsFailed as error: --- 118,125 ---- if port == 0: port = 'smtp' # Log this just once. if not self._logged: ! log.error('Cannot connect to SMTP server %s on port %s (%s)', ! config.mta.smtp_host, port, e) self._logged = True return True except SomeRecipientsFailed as error:

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Command Emails not Working
by Brinson, Jason T April 24, 2026

April 24, 2026

Hello, I have an issue where command emails (-join, -request, etc.) are getting routed to the list itself (and being moderated). I have my postfix configured according to the instructions here: https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.h… And here (for an alias domain): https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.h… Any insights would be appreciated. ----------------- Jason "Shae" Brinson (They/Them) IT Support Professional Sr. Georgia Institute of Technology College of Computing 801 Atlantic Drive NW Atlanta, GA 30332 Phone: 404-894-7065 Email: jason.brinson(a)cc.gatech.edu<mailto:jason.brinson@cc.gatech.edu>

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