Ldap errors to MTA option

Direct LDAP attribute name MTA options:  (LDAP attribute name)
The  MTA option specifies the name of a group LDAP attribute used to specify an override Envelope From address. Presence of the specified attribute on a group entry is thecritical distinction between whether a group entry is merely a group -- an e-mail auto-forwarder (equivalent to having lots of aliases) -- vs. whether the entry defines a true mailing list. In particular, the presence of such an attribute on a group LDAP entry has implications for notification messages regarding the list definition (e.g., syntactic errors in list member addresses, or syntactic errors in a list-specific Sieve filter) or regarding delivery of messages to list members, as well as for the handling of delivery  receipt requests.

Typically, the value stored in the specified LDAP attribute will be some normal email address. But two (three, as of MS 6.3) special syntaxes are also supported.

Setting the value stored in the specified LDAP attribute to an address of the form  has a special meaning. The asterisk character will be expanded into a representation of the recipient address; thus a separate copy of the list message is generated for each recipient, with each copy including the intended recipient address as a subaddress within the return address. If delivery errors subsequently occur, the subaddress will indicate which was the failing address. In some cases, when dealing with remote MTAs that generate nonstandard, uninformative delivery error messages, this can in theory be useful as a way of determining which recipient address(es) failed, even when the bounce message&#x27;s inner content is relatively uninformative. And it may make processing of such bounce messages by an automated program more convenient. However, the tradeoff is that such per-user-specific return address values require that a separate message copy be generated and sent for each recipient; for a "large" list, with many recipients in the same destination domains, this can be a large increase in overhead (a large decrease in efficiency). And with more prevalent use nowadays of standard format notification messages,  the "need" for this sort of approach, with its extra (potentially large) overhead, is much less (since the intended recipient information can instead be extracted from the standard field in the contents of a standard format notification message).

(New in MS 6.3, but not working until fix for CR # 6530591.)  Setting the value stored in the specified LDAP attribute to the forward slash character, /, has a special meaning. It tells the MTA to revert to using the original envelope From address that had been present on the incoming message, yet in all other respects use mailing list semantics. This can be useful for setting up mailing lists that report all forms of list errors to the original sender.

New in MS 6.3, the     MTA option can enable use of the $S (recipient&#x27;s subaddress) substitution in the value. This would tend to be of interest when defining a "meta-list".

For users defined via alias options, see instead the   alias option; or in legacy configuration  alias file or  alias database definitions, see the &#x5b;ERRORS_TO&#x5d; alias file named parameter.

See also:
 * Mailing lists
 * Notification messages
 * subaddressexact Option
 * process_substitutions MTA Option
 * Meta-group list definitions
 * Alias options
 * alias_envelope_from Option
 * Alias file named parameters
 * subaddressexact Option
 * Notification messages
 * Proper use of lists rather than groups
 * Direct LDAP attribute name MTA options