bounce - Postfix bounce message template format
bounce_template_file = /etc/postfix/bounce.cf
postconf -b [template_file]
The Postfix bounce(8) server produces delivery status notification (DSN) messages for
undeliverable mail, delayed mail, successful delivery or address verification requests.
By default, these notifications are generated from built-in templates with message headers
and message text. Sites can override the built-in information by specifying a bounce tem-
plate file with the bounce_template_file configuration parameter.
This document describes the general procedure to create a bounce template file, followed
by the specific details of bounce template formats.
To create a customized bounce template file, create a temporary copy of the file
/etc/postfix/bounce.cf.default and edit the temporary file.
To preview the results of $name expansions in the template text, use the command
postconf -b temporary_file
Errors in the template will be reported to the standard error stream and to the syslog
While previewing the text, be sure to pay particular attention to the expansion of time
value parameters that appear in the delayed mail notification text.
Once the result is satisfactory, copy the template to the Postfix configuration directory
and specify in main.cf something like:
bounce_template_file = /etc/postfix/bounce.cf
TEMPLATE FILE FORMAT
The template file can specify templates for failed mail, delayed mail, successful delivery
or for address verification. These templates are named failure_template, delay_template,
success_template and verify_template, respectively. You can but do not have to specify
all four templates in a bounce template file.
Each template starts with "template_name = <<EOF" and ends with a line that contains the
word "EOF" only. You can change the word EOF, but you can't enclose it in quotes as with
the shell or with Perl (template_name = <<'EOF'). Here is an example:
# The failure template is used for undeliverable mail.
failure_template = <<EOF
From: MAILER-DAEMON (Mail Delivery System)
Subject: Undelivered Mail Returned to Sender
Postmaster-Subject: Postmaster Copy: Undelivered Mail
This is the mail system at host $myhostname.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
The usage and specification of bounce templates is subject to the following restrictions:
o No special meaning is given to the backslash character or to leading whitespace;
these are always taken literally.
o Inside the << context, the "$" character is special. To produce a "$" character as
output, specify "$$".
o Outside the << context, lines beginning with "#" are ignored, as are empty lines,
and lines consisting of whitespace only.
Examples of all templates can be found in the file bounce.cf.default in the Postfix con-
TEMPLATE HEADER FORMAT
The first portion of a bounce template consists of optional template headers. Some become
message headers in the delivery status notification; some control the formatting of that
notification. Headers not specified in a template will be left at their default value.
The following headers are supported:
The MIME character set of the template message text. See the "TEMPLATE MESSAGE
TEXT FORMAT" description below.
From: The sender address in the message header of the delivery status notification.
The subject in the message header of the delivery status notification that is
returned to the sender.
The subject that will be used in Postmaster copies of undeliverable or delayed mail
notifications. These copies are sent under control of the notify_classes configura-
The usage and specification of template message headers is subject to the following
o Template message header names can be specified in upper case, lower case or mixed
case. Postfix always produces bounce message header labels of the form "From:" and
o Template message headers must not span multiple lines.
o Template message headers do not support $parameter expansions.
o Template message headers must contain ASCII characters only, and must not contain
ASCII null characters.
TEMPLATE MESSAGE TEXT FORMAT
The second portion of a bounce template consists of message text. As the above example
shows, template message text may contain main.cf $parameters. Besides the parameters that
are defined in main.cf, the following parameters are treated specially depending on the
suffix that is appended to their name.
Expands into the value of the delay_warning_time parameter, expressed in the time
unit specified by suffix, which is one of seconds, minutes, hours, days, or weeks.
Expands into the value of the maximal_queue_lifetime parameter, expressed in the
time unit specified by suffix. See above under delay_warning_time for possible
The usage and specification of template message text is subject to the following restric-
o The template message text is not sent in Postmaster copies of delivery status noti-
o If the template message text contains non-ASCII characters, Postfix requires that
the Charset: template header is updated. Specify an appropriate superset of US-
ASCII. A superset is needed because Postfix appends ASCII text after the message
template when it sends a delivery status notification.
bounce(8), Postfix delivery status notifications
postconf(5), configuration parameters
The Secure Mailer license must be distributed with this software.
The Postfix bounce template format was originally developed by Nicolas Riendeau.
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA