Alias expandable and alias nonexpandable alias options

Alias options:  and
The  alias option (analogue of the legacy configuration alias file named parameter &#x5b;EXPANDABLE&#x5d;) is used to specify that the associated  list can be expanded (and hence its contents seen) by various protocols  which may attempt such an operation. It does not mean, or imply, that the membership of the list will be expanded into message headers; for that, instead see.

The  alias option (analogue of the legacy configuration alias file named parameter &#x5b;NONEXPANDABLE&#x5d;) specifies that the associated list may not be expanded.

is the default, unless the   MTA option   has been set, in  which case the default is.

is useful in blocking the expansion of mailing lists via SMTP&#x27;s EXPN command. Note that mailing list access controls, e.g.,  ,   ,  etc., also affect the  expansion of mailing lists via SMTP&#x27;s EXPN command; the SMTP server  will only permit the EXPN if the SMTP client passes the access control  (e.g., has issued a prior MAIL FROM: command that passes the  access control).

See also:
 * Alias options
 * Alias file named parameters
 * alias_header_expansion Option
 * ldap_expandable MTA Option
 * expandable_default MTA Option
 * alias_auth_list Option
 * alias_auth_mapping Option
 * DISABLE_EXPAND