CSAIL standard configuration for a contact-point list

One common use for a mailing list is for a small number of people to receive questions, requests, or submissions of some sort. Examples would be lists for paper submissions, conference registration, incoming-student queries, tech-support help requests, or software bug reports. In this case, typically, anybody in the world can send mail to the list, and a small number of people (perhaps as few as one) are members of the list and receive those messages. (The other two use-cases we have preconfigured templates for are discussion lists and announcement lists.)

At CSAIL, the advantages of a contact-point list over a plain email alias (as you can create in INQUIR) is that a mailing list can send mail to more than one people, can (if you choose) keep archives on the web, and has facilities for automatic replies and message filtering.

The CSAIL standard template for a contact-point list specifies:
  • Maximum message size (max_message_size) of about 40 megabytes. (Since a contact-point list has few recipients, and may get messages in all sorts of formats, perhaps with attachments, from all over, we allow large messages. You can increase this a bit if you need to, although the mail systems between you and the senders will have their own limits.)
  • There’s a “List-Post:” header on messages (include_list_post_header), although when responding you’ll want to make sure to include the original message sender, who is probably not a member of the list.
  • Both automated confirmation (that the email address is valid and belongs to somebody who wants to subscribe to the list) and moderator approval are required for subscription (subscribe_policy). In the case of a contact-point list, though, you’ll probably be adding list members — the people receiving and handling incoming messages — manually.
  • New list members are not marked as needing moderator approval for their posts to the list (default_member_moderation). In fact...
  • The nature of a contact-point list is that it receives mail from anybody, so messages from nonmembers will go through to the list members without being held for moderator approval (generic_nonmember_action). Yes, this means that list members will receive some spam through the list.
  • Posts to the list do not require the list address explicitly mentioned in the message headers (require_explicit_destination). This lets you set up aliases which forward to the list, or include the list in other lists, without having to manually approve incoming messages.
Of course, you can change any of these settings via the list administrator web interface at
The information page about the list, which you can point people at to subscribe themselves or learn more about it, is

Things you should adjust

In addition to getting subscribers on your list (either by announcing the list and letting them request to be added via the web interface, or by adding them manually through the “Membership Management...” > “Mass Subscription” page), you’ll want to:
  • You should add a paragraph or two of human-readable description about your page in the info field under “General Options”. This will be displayed on your list info page. If you explain the purpose of the list there in sufficient detail, this can also be tremendously useful for TIG years down the road when all the people authorized to manage a list have left CSAIL and we’re trying to figure out whether it’s still in use.
  • Make sure some authorized people can post to the list, either by adding addresses to accept_these_nonmembers under “Privacy options...” > “Sender filters”, or by subscribing them and turning off their “mod” checkboxes under “Membership Management...” so they can post unmoderated. (Alternatively, if you want to be extra sure something unintended doesn't make it out to the list accidentally, you can leave things as they are and just manually approve legitimate postings.)
  • By default, CSAIL mailing lists are included in the list of mailing lists we host at https://lists.csail.mit.edu/mailman/listinfo . If you don’t want your list included there, you can turn off advertised under “Privacy options...” > “Subscription rules”. Anybody who knows or can guess the name of your list can still get to its own listinfo page with all the information, but leaving it off the main list will somewhat decrease the likelihood that people or bots will stumble across it accidentally.
  • If your list is archived, especially if it’s a very low-volume list, you may wish to adjust the “archive_volume_frequency” (essentially, what time period a single index page of list messages includes) under “Archiving options”. See also below.
  • And especially if this is the first list you’re administering you should really at least skim through all the configuration options so you get a sense for what you can configure. Feel free to contact us at help@csail.mit.edu for advice or if you have any questions.


Consider the content of your list when choosing whether the list archives are public (visible to anybody at all on the web) or private (visible only to the list members, or people who can guess their membership passwords). You can choose that when creating a list with the CSAIL list creation form but you can also adjust it after the fact. For instance, a list for announcements of new releases of Free or open-source software might reasonably have public archives, because you’d want people to be able to find that information on the web even if they weren’t subscribed to the list. Of course you have no control over list members sharing their passwords, so if your list is going to get any traffic that really shouldn't be found on the web you may wish to turn off archives altogether. (Then again, your list members can still share their email passwords — or have them guessed or stolen —, or manually forward list messages) The listowner’s password also works for access to the archives.

-- JaySekora - 07 Jan 2017
Topic revision: 08 Jan 2017, JaySekora

MIT Computer Science and Artificial Intelligence Laboratory


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