When an email comes into the system, the only identification is the sender's email address. The user is looked up based on the email address.
- If a matching user is not found, then the current user is assumed to be unknown, if unknown exists
- If unknown does not exist, then the email is rejected as authentication will not be possible
- If the user selected is not part of email contributor's group, then the email is rejected
The current request's user is set and all subsequent processes are run as the authenticated user. If any type of authentication error is generated, then the email is rejected. The authentication will also imply that the authenticated user may not have visibility of the target node, in which case the email is also rejected. Effectively, this means that the target recipient of the email does not exist, at least not for the sender.
The current default server configuration creates the EMAIL_CONTRIBUTORS group and adds the admin user to this group.