Mailing Lists: Restrict posting permissions to a privileged group

Most mailing lists allow any and all subscribers to post messages. In addition, an administrator may want to allow posts from other addresses, even if those users are not currently subscribed. This page describes how to specify explicitly the list of people who can post.

Consider a mailing list with a set of members M and a set of pre-designated source mail addresses who are allowed to post P. By default, a list has posting permissions set such that M is a subset of P. This page describes how to make M and P unrelated. Consequently, it also describes how to make any message post with source mail address a receive a rejection notice if a is not in P.

Prerequisites

1. Choose now how you would like to handle posting from non-authorized mail addresses.
   • Hold: posts from unauthorized mail addresses will be held for moderation.
   • Reject: posts from unauthorized mail addresses will receive a rejection notice.
   • Discard: posts from unauthorized mail addresses will be deleted, and no notification will be sent.

From here forward, we will refer to this choice as your Chosen Action.

2. Gather a list of all possible source addresses for which you would like to allow posting. From here forward, we will refer to this list as your set of Allowed Addresses.
3. Make sure you have list administrator access privileges.
4. Access the list's administrative options pages by visiting the URL

https://mailman.srv.cs.cmu.edu/mailman/admin/<listname>

You may need to authenticate with the list administrator's Kerberos principal and realm, and password.

Step 1: Whitelist the mail addressed from non-members for which posting should be allowed

1. At the top of the Administrator options pages, click the link "Privacy Options".
2. A new submenu should be visible after the page reloads. Click on "Sender Filters"
3. Under the heading Non-Member Filters, next to "List of non-member addresses whose postings should be automatically accepted.", enter the mail addresses of all non-members in your Allowed Addresses.
4. Scroll to the bottom of the page, and click the button, "Submit Your Changes".

Step 2: Disable free posting by members, and selectively enable posting by members who are in your Allowed Addresses list

1. At the top of the Administrator options pages, click the link "Membership Management"
2. After the page reloads, scroll to the bottom of the page, and select 'on' next to "Set everyone's moderation bit, including those members not currently visible"
3. Accept your changes by clicking the button "Set"
4. After the page refreshes, you should see enabled checkboxes in the column under "mod" for every member in the member list on the page. Locate the members in your Allowed Addresseslist, and de-select their appropriate checkbox in the "mod" column.

Step 3: Disallow posting from non-members that you did not whitelist in Step 1.

1. At the top of the Administrator options pages, click the link "Privacy Options...".
2. A new submenu should be visible after the page reloads. Click on "Sender Filters"
3. Toward the bottom of the page, next to "Action to take for postings from non-members for which no explicit action is defined.", select the appropriate radio button that corresponds to your Chosen Action.
4. Scroll to the bottom of the page, and click the button, "Submit Your Changes".

Step 4: Disallow posting from list members that you did not re-enable posting for in Step 2

1. At the top of the Administrator options pages, click the link "Privacy Options...".
2. A new submenu should be visible after the page reloads. Click on "Sender Filters"
3. Toward the top of the configuration section on the page, there should be an option "Action to take when a moderated member posts to the list". Select the appropriate radio button that corresponds to your Chosen Action.

Scroll to the bottom of the page, and click the button, "Submit Your Changes".