Enabling Forgery Protection
Forgery Detection is an option in your Email Settings. Enabling forgery detection will require your members to verify their e-mail address after the first message they send to a discussion list. They will simply have to reply to the verification e-mail, and once they have done so, their original message will be sent to the list.
Forgery detection protects your mailing list from messages intended to mimic a group member's address, but which is actually sent from another source, such as unsolicited e-mail marketing. GroupSpaces has a number of systems in place to prevent spam reaching your members, and only members of a list are allowed to send and receive messages on that list.