The
Date: header specifies the date and time that the
mail message was originally sent. All mail messages must include this
header line. Consequently, the Date: header must
be declared in the configuration file like this:
H?D?Date: $a
The $a macro ($a) is
mandatory in the field for this header. The value in
$a is the current time in RFC2822 format. (See
Section 5.1 in RFC2822 and Section 5.2.14 in RFC1123.) Only the
$a macro should be used with the
Date: header because it is the only one that is
guaranteed to contain the current date and time in RFC2822 (and
RFC1123) format.
The ?D? flag is always included with the
Date: declaration in the configuration file. All
the standard delivery agents always include an F=D
flag (F=D). The ?D?
allows custom delivery agents to be designed that do not need a
Date: header.
