This is a collection of LDAP schemas that could be used in a virtual mail environment consisting of Postfix, Dovecot and Roundcube.
postfix-book.schema was originally available from http://www.postfix-buch.com/download/postfix-book.schema.gz but is no longer around. Two new attributes have since been added to further enhance the schema to avoid the need of loading multiple different mail specific schemas. These attributes include:
mailSieveRuleSource
mailForwardingAddress
Both Postfix and Dovecot benefit from using postfix-book.schema as their primary schema source.