The remainder of this document is a description of all Postfix configuration parameters.
The numerical Postfix SMTP server response code for an access(5) map "defer" action, including "defer_if_permit" or "defer_if_reject".
Prior to Postfix 2.6, the response is hard-coded as "450".
The parameter name must contain only characters from the set [a-z A-Z0-9_].
An undefined parameter value is replaced with the empty value.
The "" is required for "value1", optional for "value2".
This form is supported with Postfix versions ≥ 3.0.
Specify an empty table name to keep the information in volatile memory which is lost after "postfix reload" or "postfix stop".
This is the default with Postfix version 2.6 and earlier.
Parameters not explicitly specified are left at their default values.