Ldap domain attr canonical MTA option

Direct LDAP attribute name MTA options:  (LDAP attribute name)
The  MTA option names the domain LDAP attribute, by default ,  used to store the canonical domain name.

In Schema 1 mode, any domain alias entry needs such an attribute pointing back to the "real" (canonical) domain name. And in either Schema, any cases of multiple actual (non-alias) domain entries with "overlapping" users require use of such an attribute.

Note that the mapping table domain map attribute substitution    returns either the value of the LDAP attribute named by the   MTA option (so normally the value of  the   LDAP attribute), or if no such  LDAP attribute is set, returns the domain name.

See also:
 * Direct LDAP attribute name MTA options
 * Mapping entry templates