If you are provisioning an LDAP Schema 2 directory with Communications Suite Delegated Administrator:
See preferredMailHost for a definition of how to use this attribute with Schema 2.
If you are provisioning an LDAP Schema 1 directory with iPlanet Delegated Administrator, use the following definition:
Used to set the mailHost attribute of newly created users in this mail domain. When a user is created, the mailHost attribute of the user entry is filled by the value of preferredMailHost.