Currently all users created by the autocreate=true option in the mail service are created with the email address. As most of our users have LDAP accounts (with the same name as the username in the email) it would be nice to create accounts for them that can be used with the LDAP. This could be done in two ways that I can think of: the easier (and one I would at some level prefer) is to have an ignore domain flag in the service options. We would set ignore_domain=example.com and it would create new users with just the local part of their email addresses.

The other way would be to do some validation/checks on the backend data source, but that is going to be a great deal more complex.