Carnegie Mellon University School of Computer Science

Frequently Asked Questions: Mailing Lists 

Our mailing list system has a number of features that enable granular control over recipient lists, message sizes, forwarding functionality and approval mechanisms among other features that centralize and facilitate ease of list management.

Below you will find some commonly asked questions. If your question is not found on this, you can contact us or submit feedback via our form (at the bottom of this page).

To subscribe new members, go to the "General Options" page for your list and find the "Configuration Categories" section:

Click the "Membership Management" link

Click the "Mass Subscription" link

Add new members by entering their addresses, one per line, in the text window. You can use a bare-address form, such as, or either of three more complete forms that will also populate the list member's "Name" field automatically:


"Edward Xample" <>

(E. Xample) (Edward Xample)

Alternately, you can upload a text file of addresses:

Click on the "Browse" button below the text-entry window

Specify your source file

Click "OK"

The Subscription tool does not verify email addresses, so review your new entries carefully before proceeding.

Finally, click on "Submit Your Changes"

To unsubscribe list members:

Go to the "General Options" page for your list and find the "Configuration Categories" section

Either: Scroll down to the "Membership List" section and click the "unsub" box for the relevant members

Or, if you prefer the "Mass Removal" tool instead, click on its link:

Enter one or more email addresses in the text window

Alternately, you can upload a text file of addresses: Click on the "Browse" button below the text-entry window. Find the file, then click "OK."

Click on "Submit Your Changes"

To allow unrestricted posting:

Go to your list's "General Options" page, then to "Privacy Options" > "Sender Filters."

Scroll to page bottom and select "Accept" next to the option "Action to take for postings from nonmembers for whom no explicit action is defined."

Finally, click the "Submit Your Changes" button

If, after reviewing the "Privacy Options" > "Sender Filters" section of your list's administrative pages, you still do not see a way to specify the desired behavior, you may want to define a privileged group (a mixture of members, administrators, and nonmembers) that identifies the only people allowed to post.

Mailman may be having difficulty parsing bounce messages returned by software on some destination system. Although Mailman can handle most such warnings for you, error-message formats are not standardized, and some messages can confuse the system. To alleviate the problem, you have two choices:

Remove the offending addresses from your membership list:

Go to the "General Options" page for your list and click the "Membership Management" link

When the page reloads, click the "Mass Removal" link, near where you previously clicked

In the form that pops up, enter the rejected mail addresses

Click the "Submit Your Changes" button

Turn off bounce notifications:

Go to the "General Options" page for your list and click the "Bounce Processing" link at page top

Scroll down to the "Bounce detection sensitivity," area and find the option "Should Mailman send you, the list owner, any bounce messages that failed to be detected by the bounce processor? ..."

Select "No,"

Click the "Submit your changes" button

When a mailing list's membership gets large, the interface displays the member list in alphabetic chunks. To see the complete list on a single roster page:

Go to the "General Options" page for your list

Under "Other Administrative Activities," select "Go to the general list information page"

Click on "Visit Subscriber List"

Depending on the type of list, the amount of traffic it gets, and the amount of off-topic messages it attracts, you may wish to consider list moderation, in which all (or just some) incoming mail is held for inspection before delivery to list members.

While moderation is an effective way to ensure that only appropriate mail propagates through the list, the tradeoffs include extra work and delays in forwarding messages. Administrators can moderate for themselves or can designate separate Moderators to handle pending mail.

Set up Moderation options on the "Sender Filters" page under "Privacy Options."

In digest mode, incoming mail is collected and only sent out periodically in one large message called a "digest." Each new digest continues where the last one ended. While this option is not as popular as it once was, some users still appreciate receiving mailing-list traffic in large chunks this way.

The option can be set on a per-user basis. Users can direct the Mailman server to deliver the list as a digest themselves, or the Administrator can change this setting for individual users under "Membership Management" by setting the user's "Digest" flag

This error indicates that the Kerberos instance under which you authenticated via WebISO is not listed as owner of the mailing list whose administrative pages you are attempting to access. The list's owner is shown near page bottom-left. You must go back and reauthenticate with that identity.

Mailman's filter rules provide flexible screening of incoming mail and can be configured to look for specific headers set by the PureMessage tagging service. On encountering such headers, Mailman can take several actions. Commonly, mail is either held for Moderator review (to see if it really is spam) or simply discarded (often a useful policy for high-traffic lists). Configure your spam filters under "Privacy Options" in the "Spam Filters" subsection:

To catch messages that PureMessage considers spam, add a rule with:

Spam Filter Regexp: X-Spam-Warning:

Action: Discard

To catch virus warnings, add a rule with:

Spam Filter Regexp: Subject:.*PMX:VIRUS

Action: Discard

For help in creating more complex filters, feel free to contact the SCS HelpDesk.

You can enable archiving for a mailing list from the Archiving Options page of the Mailman list administration site. To turn on archiving, click Archiving Options, set Archive messages? to Yes and click Submit Your Changes.

The Archiving Options page also allows for you to update other settings including whether archives should be public or private. To access archives

Please note that attachments associated with list archives will last for two years. Attachments associated with lists that have archiving turned on will be automatically expunged when the message with the attachment is older than two years.

If you have any questions or need support, please contact the SCS Help Desk via phone at 412-268-4231, via email at or submit a ticket.