In order to enable direct LDAP, the following MTA options need to be set:
ALIAS_MAGIC=8764 ALIAS_URL0=ldap:///$V?*?sub?$R USE_REVERSE_DATABASE=4 USE_DOMAIN_DATABASE=0 REVERSE_URL=ldap:///$V?mail?sub?$Q
If vanity domains are to be supported, the following additional options must be set:
DOMAIN_MATCH_URL=ldap:///$B?msgVanityDomain?sub? \ (msgVanityDomain=$D) ALIAS_URL1=ldap:///$B?*?sub? (&(msgVanityDomain=$D)$R) ALIAS_URL2=ldap:///$1V?*?sub?(mailAlternateAddress=@$D)
Note that the last of these options also handle the case of wild carded local parts in hosted as well as vanity domains. If wild carded local part support is desired but vanity domain support is not, the following option should be used instead:
The filter ssrd:$A clause needs to be removed from the ims-ms channel definition in the MTA configuration file (imta.cnf).