Unique id template MTA option

Message archiving and hashing MTA options:  (string)
The  MTA option specifies a template used to convert an address for a "local" user into a  unique identifier. The template&#x27;s substitution vocabulary is the same as that for delivery options; (see the  MTA option, and especially the permitted LDAP URL substitution sequences). The resulting unique identifier is intended for use by message archiving tools. So for instance a site could set unique_id_template=$M@$D to use each user&#x27;s      as that user&#x27;s unique identifier.

See also:
 * Message identifier generation
 * Message archival and hashing MTA options
 * delivery_options MTA Option
 * LDAP URL substitution sequences