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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 efficiently. 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 address. 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 (openbsd.org) 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". Digests ------- 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 details. 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 separately. 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: LISTNAME@openbsd.org 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 setting. 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 eliminatecc prefix replyto selfcopy 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 To Cc JKL configset LISTNAME message_headers <<MNO To: $WHOAMI 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 duplicated. 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 command: configset LISTNAME attachment_filters <<LPQ text/html | discard text/html | format LPQ 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 e-mail. 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 details. 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 information. 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 soandso@example.com." 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 0.1201103110. For a list of all help documents, send the following command: help topics in the body of a message to majordomo@openbsd.org.
For assistance, please contact the openbsd.org administrators.
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