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                   Introduction to the Delivery Process

When a message is delivered to the subscribers of a mailing list, 
Majordomo may make some alterations to the content of the message.
Among other features, a mailing list can be configured to...

  * Add unsubscription instructions to the end of the message.
  * Change the Subject header to show the name of the mailing list.
  * Remove or reformat attachments.
  * Change the Reply-To header to direct replies to the mailing list.
  * Bundle the messages into a digest.

Some portion of the addresses that are subscribed to a mailing list
may be temporarily or permanently unavailable.  When delivery to
one of these addresses fails, an error message ("bounce") is sent
to the list owners.  Majordomo's flexible framework for coping 
with bounces is discussed later in this document.

Majordomo relies on another computer program (the message transfer agent,
or MTA) to deliver the mail.  The last part of this document outlines 
ways in which you can help Majordomo and the MTA to cooperate more 

The examples in this document assume that you know how to use your 
list's administrative password.  Please review "help admin_passwords",
if you have not already done so.  In each example, replace LISTNAME
with the name of your mailing list.  Replace ADDRESS with a valid e-mail

Delivery classes

Whether or not a subscriber receives a message that is posted to a
mailing list will depend upon that subscriber's delivery class.  
There are four main delivery classes: digest, each, nomail, and unique.  

  * Subscribers in the digest class receive messages in bundles, rather 
    than individually.   
  * Subscribers in the each class receive each message.

  * Subscribers in the nomail class receive no messages.

  * Subscribers in the unique class receive each message, unless the
    same message was previously posted to another mailing list
    in the same domain ( to which the subscriber is subscribed.

When someone first joins a mailing list, their delivery class is
usually determined by the default_class configuration setting (see
"help configset_default_class" for more details).  However, it
is also possible to subscribe and choose the delivery class at
the same time.  For example, the following command:

  subscribe-set LISTNAME digest

will subscribe an address to a mailing list and set its delivery
class to "digest" at the same time.  For more information, please
refer to "help admin_subscribers".


There are two situations in which a digest might be delivered.
The trigger mechanism (see "help configset_triggers") will check once 
an hour to see if a digest is ready for delivery.  In addition, 
the digests are checked every time a message is posted to a mailing list.

The digest configuration setting offers a lot of flexibility in how
and when digests are delivered.  Briefly, you can choose:

  * The hours of the day, and days of the week, during which digests
    can be delivered.

  * The minimum and maximum size or number of messages in a digest.

  * The maximum acceptable age of undelivered messages in a digest.

  * The minimum time between digest deliveries.

  * The default format of a digest.

  * What information to display about each message in the table
    of contents.

  * In what order the messages in the digest should be sorted.

The digest command can be used to force a digest to be delivered
immediately.  See "help configset_digests" and "help digest" for more

Headers are added to every digest as determined by the
message_headers, precedence, reply_to, and sender configuration
settings.  For more information, see the following documents:
   help configset_message_headers
   help configset_precedence
   help configset_reply_to
   help configset_sender

The rest of this document deals with messages that are delivered

Delivery settings

There are two message headers that can vary from subscriber to subscriber.
A prefix can be added to the Subject of a message to make it clear to
the readers on which mailing list the message was posted.  For example,
in this header...

  Subject: Re: [radish-list] Purple podding radishes

..."[radish-list]" is the subject prefix.  This is controlled by
the "prefix" personal setting.

Also, people who want their replies to always go to the address of the
list can choose to have a Reply-To: header added
to each message.  This is controlled by the "replyto" personal setting.

Subscribers who post messages can choose whether or not to receive copies 
of their own messages.  This is controlled by the "selfcopy" setting.

If a message is sent to a mailing list, and the address of a subscriber
appears in the To or Cc headers of the message, the subscriber will
usually receive two copies.  Subscribers can forego receiving a second
copy from the list; this is controlled by the "eliminatecc" personal

Which of these personal settings are given to new subscribers is determined
by the default_flags configuration setting.  For example, to turn on
all four of these features, use the following command:

configset LISTNAME default_flags <<LLL

The following command would turn on all four settings for someone who
is already subscribed to the list:

  set LISTNAME eliminatecc,prefix,replyto,selfcopy ADDRESS

For more information, read the following documents:
   help configset_default_flags
   help configset_override_reply_to
   help configset_reply_to
   help configset_subject_prefix
   help configset_subject_re_pattern
   help configset_subject_re_strip
   help set

Changing the headers

Aside from the delivery settings in the last section, any changes made
to a message will affect all of the people who receive separate copies
of the message.  The message_headers and delete_headers configuration
settings can be used to add or remove any header in a posted message.
The delete_headers changes are applied first, so the two settings can be
used in tandem to replace existing headers. For example, the following
commands will remove any existing To or Cc headers, and place the list
address in the To header of the message.  This could be used to cut down
on duplicates and prevent cross-posting.

configset-append LISTNAME delete_headers <<JKL

configset LISTNAME message_headers <<MNO

In addition to the message_headers setting, the precedence and reply_to
settings will also add headers to outgoing messages.  We recommend that
you do not include a Reply-To or Precedence header in the
message_headers setting, because it may result in headers being

The reply_to and override_reply_to configuration settings will only
cause a Reply-To header to be added to messages sent to people whose
"replyto" personal setting is turned on.  In contrast, the
delete_headers, message_headers, precedence, and purge_received settings
affect every message that is sent to a subscriber individually.

See the following help files for more details:
   help configset_delete_headers 
   help configset_message_headers
   help configset_override_reply_to
   help configset_precedence
   help configset_purge_received
   help configset_reply_to

Fronters and footers

Sometimes, administrative notices or advertisements are automatically
included at the beginning or end of mail messages.  These notices
are called fronters and footers.  Although they can be added easily
to plain text messages, including them in HTML or plain text/HTML
alternative messages is problematic.  As a result, fronters and
footers may be added to some messages and not to others.

See "help configset_message_fronter" and "help configset_message_footer"
for more details.

Discarding or reformatting attachments

The attachment filters can be used to change or discard parts of a 
posted message.

To remove all of the text/html parts from multipart messages, and
convert all single-part HTML messages into plain text, use the following

configset LISTNAME attachment_filters <<LPQ
text/html | discard
text/html | format

This rule is useful if you want to include a fronter or footer in each 
message, or want to avoid the security problems associated by HTML in

See "help configset_attachment_filters" for more details.

Delivery failures (bounces)

Some of your list's subscribers may not receive every message.  A
mailbox that is full, an expired e-mail address, or a technical
malfunction can cause an error message (a "bounce") to be sent to the
list administrators.  Majordomo has several features which allow you to
cope with bounces automatically.

When a bounce message arrives, Majordomo will try to identify the
address of the recipient and collect statistics about recent bounces
for that address.  Then, the bounce_rules setting will determine if
the recipient should be removed from the mailing list, and whether or
not the bounce message should be forwarded to the list administrators.
See "help configset_bounce_rules" for more details.

Usually, bounce messages are sent to the list owners.  The
bounce_recipients setting can be used to forward the messages to a
different address.  See "help configset_bounce_recipients" for more

Is is not always possible for Majordomo to identify an address that is
bouncing.  The bounce_probe_frequency and bounce_probe_pattern settings
can be used to send individual copies of each posted message to some
subscribers, which makes the identification of bounceing addresses
easier.  See "help configset_bounce_probe_frequency" and 
"help configset_bounce_probe_pattern" for more details.

Information about bounces is stored in the subscriber database for a
limited amount of time.  See "help configset_bounce_max_age" and 
"help configset_bounce_max_count" for ways to control the amount of
information stored in the database.

The who-bounce command can be used to display information about
subscribers whose addresses have been experiencing delivery failures.
See "help who" for more details.

Delivery rules (advanced topic)

How quickly a posted message will be delivered by the MTA depends upon who 
is subscribed to a mailing list, and how Majordomo handed off the message.
For example, if 35 addresses on the list use the same service provider,
it may be more efficient to deliver the message to all of them at once.
On the other hand, if the list has tens of thousands of subscribers, it
is more efficient to separate them into smaller groups during delivery.

For security reasons, only site or domain managers can change the delivery
rules for a mailing list.  See "help configset_delivery_rules" for more 

Personalizing messages (advanced topic)

It is possible to configure a Majordomo list to deliver a separate copy
of each message to each recipient.  This makes it possible to place
the address of the recipient in the To: header, or to add a footer
that says "You are subscribed to the LISTNAME list as"
For more details, see the section on "Configuration templates" in
the "help admin_config" document.

See Also:
   help admin
   help admin_commands
   help admin_config
   help admin_documents
   help admin_monitor
   help admin_moderate
   help admin_passwords
   help admin_subscribers
   help digest
   help post
   help set
   help who

This is the "admin_delivery" help document for 
Majordomo 2, version 0.1200401130.

For a list of all help documents, send the following command:
   help topics
in the body of a message to

For assistance, please contact the administrators.
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