All E-Mail Addresses (includes Directory):

Will return results based on all mapped email addresses within a postoffice. This includes any email address in the directory for the postoffice, as well as the group and list external email addresses.

Directory Contents (Default):

Will return results based on directory members (Global contact list).

Default mailbox addresses (aliases as proxyaddresses):

Will return results using the default email address for a mailbox. All other mapped email addresses for the mailbox are returned as "proxyaddress" attributes. Selecting this option also shows two more available options:

Also return mail attribute as proxyaddress:

Normally the default email address is not also returned as a proxyaddress. This option returns the default email address also as a proxyaddress attribute.

Return directory entries for those without mailboxes:

Also returns all the email addresses in the global directory, even if they have no attached local mailbox.