When a domain is created a default set of mailboxes are created as follows:
Admin (or the name specified when defining the root.login name in the configuration wizard)
This is the default administrator for the domain
This is a group mailbox containing all the administrators of the domain. Members of this group are only granted access to WebAdmin if the mailbox itself is granted administrator access. See Web Administration
A special mailbox for handling list mailbox delivery status notifications
A group mailbox into which FTGate adds all new user mailboxes created. Mailboxes can be removed from the group to hide them from other users.
A mailbox that deletes all mail sent to it.
An alias for administrators. Internet RFC’s require that a postmaster be defined.
A mailbox that processes system commands. See Mailbox Overview