Email at MIT

Preventing Unsolicited Email from Getting to Your Mailing List Members

IS&T offers support for Mailman mailing lists as an alternative to the simpler “moira” or Athena lists. Mailman has several features that make it appealing, especially for large lists:

• Moderation of list email, including “announce-only” settings
• Filtering based on sender and other headings such as SpamAssassin tags
• Simple archiving
• Automatic processing of bounced email
• An administrative web site for each list

However, given Mailman’s extensive features for list administration, it may not be the first choice for small lists. Also, Mailman has a limited ability to manage nested lists and sublists. Another consideration is that you can’t use Mailman lists as groups for AFS permissions or htaccess permission to restrict access to pages served by https://web.mit.edu.

Login Options
Mailman lets list owners administer their mailing lists by logging into an administrative interface with a password or by logging in with their MIT personal certificate. The standard login page is

https://mailman.mit.edu/mailman/admin/LISTNAME

where LISTNAME is the name of the mailing list.

If you administer several Mailman lists, you may prefer a single login using certificates rather than remembering multiple passwords. To log in using your MIT certificate, go to a slightly different URL

https://mailman.mit.edu:444/mailman/admin/LISTNAME

(making sure there’s an “s” at the end of https: and adding “:444” after mailman.mit.edu).

If you created your Mailman list using the automatic list creation service, you will be logged in using your certificate. You may continue to do this, or you can set the password for the list using the Passwords option. Note that any administrator of a Mailman list with an address other than username@mit.edu must use the password login option.

Spam Filtering
Your Mailman list can be set up so that only members can post messages to it (e.g., a private discussion list), or so that only a particular set of people can post messages to it (e.g., a departmental announcement list). This sort of moderation generally blocks all incoming spam from being posted to the list.

However, you may want your list to be able to receive messages from outside addresses, while still cutting down on the amount of spam received (or the amount of spam that the moderator has to discard). Spam filters – in the Privacy Options section on the list’s administrative web page – will let you add additional filtering to your list. If you add a filter of X-Spam-Flag: yes, then messages that match MIT’s default spam criteria (a score of 10.5) will be filtered. If you want to fine-tune the spam scoring, you can use a filter along the lines of

X-Spam-Level: \*{7,}

This filter matches everything with a spam score of 7 or above.

Keep in mind when setting up filtering that instructions to “discard” (throw away the mail silently) or “reject” (throw away the mail, but notify the sender that it has been rejected) will delete mail permanently. Rather than set up filters to discard or reject immediately, it may be safer to set them to “hold” first. This lets you look through the messages that have been flagged by the filters, and make sure that nothing has been flagged that you didn’t want thrown away. Once you’re sure that your filters are working the way you want, you can change them over to discard or reject.

Support for Mailing Lists
If you need help determining whether a Mailman or Athena list best fits your needs, or have other questions about mailing lists at MIT, contact User Accounts at <accounts@mit.edu> or 253-1325.

This page was originally an article by Laura Baldwin in the IS&T Newsletter March/April 2006 issue.