Mailing Lists

Local Aliases versus Mailing Lists on the IMSS Servers

If you just want an alias that ONLY YOU will use to send electronic mail to a group of people, you should check the documentation for the mail program you use. It should have some way of creating "aliases" or "alias groups" to let you do this. If you want other people to be able to send to the list, then you'll want to to request that a list be set up for you on the IMSS servers.


IMSS uses mailing list management software called Mailman. Some of its important features are:

  • Subscription, unsubscription, and list administration are done using a web-based interface.
  • The list owner has complete control of their list. This allows the owner to change their list preferences whenever they desire and eliminates the need to contact IMSS for list changes.
  • Messages marked as spam by IMSS' Spam Flagging Service are automatically discarded or put into a queue for the moderator/owner to approve or delete. Users should see much less spam as a result.

If you would like a mailing list,submit a request at (request type IMSS-->Email & Calendar-->Create a Mailing List).The following information will be necessary:

  • The name of the list, suitable for a mailing address (i.e. letters, numbers, and hyphens only; no spaces). List names may be from 2 to 32 characters in length.
  • The email address of the contact person.
  • A subscription preference. The available preferences are as follows:
    • Public subscription - Anyone may join the list, and may leave without owner approval.
      (Note that for publicly advertised lists, public subscription that does not require moderatorapproval for new subscription requests may increase the chance that your list will be subscribed to and used by spammers.)
    • Caltech-only subscription - Anyone may join the list if they submit an email address ending in, and may leave without owner approval.
    • Private subscription - The list owner has total control over who is on the list.
  • A posting preference. The available preferences are as follows:
    • Public posting - Anyone may send messages to the list.
    • Caltech-only posting - Messages not from addresses with wlll be held for moderator approval.
    • Members-only posting - Messages not from addresses subscribed to the list will be held for moderator approval

Please note that, by default, lists with the 'public' or 'Caltech-only' subscription profiles have a 40 kilobyte size limit on messages sent to the list, and put the name of the list on the subject line of all messages. If you want one of those subscription profiles but don't want either of the above features, please let us know.

Once the list is created, the owner will receive an email from the Mailman system that contains the admin URL and password. The system assigns a randomly generated password, though this can be changed from within the admin interface. The e-mail will also contain the URL that users need to know if they want to subscribe or unsubscribe, along with several other pieces of information about your list.

Once you sign into the admin interface, you will notice that you can modify almost everything to your liking. One item some owners prefer is to change the list so that only a few people can send to list members and everyone else is moderated. Owners can change whether spam is put in a moderation queue or is discarded automatically. Instructions for this are included in the welcome message you will get when your list is created.

The owner will also be added to the "" mailing list, which is used to send out announcements regarding changes, downtime, tips, and other messages relating to the service.

We've compiled a list of Frequently Asked Questions about configuring Mailman and administering lists, but if you think you will need assistance configuring Mailman, please contact us at (request type IMSS-->Email & Calendar-->Mailing List Issues)or call us at x3500.

Go to the IMSS Mailing List System.