Owner’s Guide: Maintain a Mailman list

Last updated: August 26, 2022
Audience: StudentsInstructorsStaffIT Staff / Technical

This information applies to: New Mailman

Please note: This documentation is still undergoing quality check. The final version will be published soon.

Control access to your list

Mailman allows list owners to control access to the list and messages posted to the list. Owners can require approvals for subscriptions, revoked subscriptions, and message postings.

Require approval to subscribe or unsubscribe

List owners can require approval in order for people to subscribe to or leave the list.

  1. Log in to your list administration screen.

    • In the address window of your web browser, enter listname.uw.edu where listname is replaced with the name of your list. For example, if your list is uwsports, you would enter uwsports.uw.edu.
    • When you reach the list web page for your list, near the top of the page, click Log in, and then enter your UW NetID and password.
  2. In the menu at the top of the page, click Settings. In the left navigation click Member Policy.
  3. To require owner or moderator approval to subscribe, set Subscription Policy to Moderate. You can also require subscribers to confirm their subscriptions.
  4. To require owner or moderator approval to unsubscribe, set Un-Subscription Policy to Moderate. You can also require people who unsubscribe to confirm leaving the list.
    • Note: For most lists, we do not recommend to requiring approval for unsubscribing because it adds unnecessary work.
  5. When finished, click Save changes.

See Member Policy for more list membership options.

List moderation settings

When you request a new list, you can specify whether it will be moderated. You can change the moderation for list members and non-members.

Require approval for all postings from list members

  1. Log in to your list administration screen.

    • In the address window of your web browser, enter listname.uw.edu where listname is replaced with the name of your list. For example, if your list is uwsports, you would enter uwsports.uw.edu.
    • When you reach the list web page for your list, near the top of the page, click Log in, and then enter your UW NetID and password.
  2. In the menu at the top of the page click Settings and in the left navigation click Message Acceptance.
  3. Go to the Default action to take when a member posts to the list.
  4. Select Hold for moderation.

Require approval for all postings from specific list members.

  1. Log in to your list administration screen.

    • In the address window of your web browser, enter listname.uw.edu where listname is replaced with the name of your list. For example, if your list is uwsports, you would enter uwsports.uw.edu.
    • When you reach the list web page for your list, near the top of the page, click Log in, and then enter your UW NetID and password.
  2. In the menu at the top of the page click Users and select Members, and locate the list member.
  3. Click Member options
  4. Scroll down to Moderation and select Hold for moderation.
  5. Click Save changes
    • Note: If you want to only moderate a few list members, you will need to specify each one individually. There currently is not a good way to make bulk changes.

You can set other moderation actions for individual users in the Moderation section.

  • List default follows the list’s default member action.
  • Hold for moderation holds the message for approval by the list moderators.
  • Reject automatically rejects the message and sends a rejection notice (aka, “bounce”) to the post’s author. List owners can configure the text of the bounce notice.
  • Discard discards the message, without notifying the post’s author.
  • Accept automatically accepts any postings without any further checks.
  • Default Processing runs additional checks and accepts the message.

Control your moderation notifications

To control when you receive the moderation notification (immediately or once daily):

  1. Log in to your list administration screen.

    • In the address window of your web browser, enter listname.uw.edu where listname is replaced with the name of your list. For example, if your list is uwsports, you would enter uwsports.uw.edu.
    • When you reach the list web page for your list, near the top of the page, click Log in, and then enter your UW NetID and password.
  2. In the menu at the top of the page, click Settings and select Automatic Responses from the drop-down menu. Scroll down to Admin immed notify setting.
  3. By default, notifications are sent immediately. To receive notifications daily, select No, to receive notifications immediately, select Yes.

Discard posts from non-members

  1. Log in to your list administration screen.

    • In the address window of your web browser, enter listname.uw.edu where listname is replaced with the name of your list. For example, if your list is uwsports, you would enter uwsports.uw.edu.
    • When you reach the list web page for your list, near the top of the page, click Log in, and then enter your UW NetID and password.
  2. In the menu at the top of the page click Settings and select Message Acceptance.
  3. In the Default action to take when a non-member posts to the list setting, select Discard*.
  4. Scroll to the bottom of the page and click Save changes.
    • *You can also select to hold messages from non-members for moderation, reject the messages with notification, accept immediately, and process using defaults.

Turn on Emergency Moderation

If your activity on your list gets out of control, you can enable emergency moderation which holds all list traffic for moderation.

  1. Log in to your list administration screen.

    • In the address window of your web browser, enter listname.uw.edu where listname is replaced with the name of your list. For example, if your list is uwsports, you would enter uwsports.uw.edu.
    • When you reach the list web page for your list, near the top of the page, click Log in, and then enter your UW NetID and password.
  2. In the menu at the top of the page, click Settings.
  3. In the left navigation, select Message Acceptance.
  4. Scroll down to Emergency Moderation.
  5. Select Yes.
  6. To return your list to normal operations, change this option back to No.

Moderation requests for an unmoderated list

Even if your list is configured as unmoderated, you may receive moderation notices. Each moderation notice will give a reason for why the message was moderated. Following are examples of each type of moderation message:

Reason: Message body is too big

Explanation: Mailman will compare the size of the incoming message to the size allowed for each list. By default, any message over 40 KB is held for moderation. Any message over 10 MB will be returned to sender as undeliverable.

Setting: To control the maximum message size allowed for your list, go to General Options and look for the max_message_size setting at the bottom of the page. You can set it to 0 for the maximum allowable size of 10 MB.

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Reason: Post to moderated list

Explanation: Individual subscribers can be moderated (rather than having the entire list moderated for everyone). This is the reason that will be given if a moderated member sends a message to the list.

Setting: An individual’s moderation can be turned on and off on the Membership List (under Membership Management). The setting that controls what is done with a message sent by a moderated member is under Privacy Options; Sender filters and is called “member_moderation_action.”

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Reason: Post by non-member to a members-only list

Explanation: A non-member tried to post to a list that is configured to only allow members to post.

Setting: The “generic_nonmember_action” setting under Privacy Options > Sender filters controls what happens to messages from non-members. It can be set to either accept messages (no moderation), hold for moderation, reject, or discard messages.

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Reason: Message has implicit destination

Explanation: By default, Mailman looks for the list’s address in the To or Cc fields of incoming messages. If the address is not explicitly given in the To or Cc fields (e.g., if the list has been blind carbon copied or if the list is subscribed to another list to which the message was originally sent), the message will be held for approval.

Setting: You can configure the list so that the address is not required to be in the To or Cc fields by going to Privacy Options > Recipient filters and setting the “require_explicit_destination” setting to No.

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Reason: Too many recipients to the message

Explanation: Mailman will examine the number of email addresses listed in the To or Cc fields of incoming messages. By default, Mailman will hold for moderation any message that contains more than 10 addresses in these fields (the list’s address is only one address and the number of subscribers on the list does not have an effect on this setting).

Setting: You can change the default setting for “max_num_recipients” under Privacy Options > Recipient filters. Change this setting to 0 for no limit.

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Reason: Message has a suspicious header

Explanation: Your Mailman list can be configured to moderate messages with specific headers (e.g., “Subject: On Vacation”). If a message contains such a header, it will be held for moderation.

Setting: The “bounce_matching_headers” setting under Privacy Options > Spam filters contains all headers that Mailman is configured to look for. You can add or delete headers from this list.

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Reason: Posting to a moderated newsgroup

Explanation: Your Mailman list can be configured to also send copies of messages to an existing newsgroup. You can specify whether or not that newsgroup is moderated in the MailNews Gateways section of the admin pages.

Setting: If the “news_moderation” setting under MailNews Gateways is set to Moderated, messages sent to your Mailman list will be held for moderation. Please note that even if the list is not configured to be linked to a newsgroup, the “news_moderation” setting will still affect list moderation.