SymptomsBy default if you create mailing list, everyone may send correspondence to the list. How do I configure the list, so only members may send mail to the list?
This can be configured through WEB Mailman interface. You should login into as list administrator and enable "Restrict posting privilege to list members" option.
By default a mailling list is created with "Posts must be approved by an administrator" option, that means all messages must be approved by moderator before they posted to the list. So, if such option is disable and unwanted mail is posted to the list, you may enable it back and moderate incoming messages.
Please see Mailman documentation for more information at http://www.gnu.org/software/mailman/docs.html.