Generating delay notifications for deferred low-priority mail

When Domino® routes all low-priority mail within the specified low-priority time range, the affected messages can remain in MAIL.BOX for a significant amount of time. A delay might not be noticed by users whose messages were intentionally sent as low-priority, but occasionally message priority is reduced unexpectedly, as, for example, when messages greater than a specified size are sent at off-peak hours. Unexpected routing delays can cause concern and result in calls to the help desk.

You can configure the Router to notify senders when low-priority mail is delayed. Of course, you should also educate users about your policy on routing low-priority mail. When delay notifications are enabled, the Router delivers a message to the sender of the delayed message that explains that the message is being held until the specified routing time.

When a message is delayed, users receive an informational Delay report, which identifies the number and addresses of the intended recipients and indicates that transfer is delayed until the low-priority time range. The notification includes the headers of the original message, but not the message body, and explains that no additional user action is required to deliver the message. You can also customize the text of the notification to include additional information.

You can have the Router deliver delay notifications for every low-priority message held; for messages held because the sender designated them as low-priority; or for messages held because Domino® changed the priority for policy reasons -- as, for example, when a size restriction forces a change to the routing priority of a large message.

For information on configuring Domino® to send delay notifications when it holds low-priority messages, see the topic Setting transfer limits and for information on setting size limits on messages, see the topic Restricting mail routing based on message size.

Normally, a server sends only one delay notification for each message. However, restarting a server or Router can result in duplicate delay notifications. Also, a user may receive multiple delay reports for a message that is delayed by servers at successive hops along the routing path. Servers at successive hops can each send a delay report if delay notifications are enabled and they each receive the message before their configured low-priority routing time and buffer time.

For example if a first hop server has a low-priority range of 12:00 AM to 3:00 AM and receives a low-priority message at 11:30 PM, it generates a delay notification. At the start of the low-priority routing time, the server routes the message to the next hop server. If this server also defers low-priority mail and has a low-priority range of 4:00 AM to 6:00 AM, it generates an additional delay notification.

By default, the Router does not send delay notifications for low-priority messages that a user sends within the low-priority time range or a buffer time of 30 minutes before the start of the time range. You can alter the default behavior by adding the variable RouterLPDelayNotifyBufferTime to the NOTES.INI file and setting its value to the length of the desired buffer time, in minutes. For example, if you would like to prevent low-priority messages sent within an hour of the start of the time range from generating a delay notification, enter the following line in the NOTES.INI file:


Exceptions to sending delay notifications

The Router does not send delay notifications in the following cases:

  • If you enabled the Ignore message priority setting in the Configuration Settings document, on the Router/SMTP > Advanced > Controls tab, Advanced transfer controls section.
  • When inbound SMTP messages include a Delivery Status Notification (DSN) request that is set to NOTIFY=NEVER. Only DSN requests with the value NOTIFY=DELAY result in delay notifications.
  • If the delayed message is a delivery failure report. For example, if a message is demoted to low priority and delayed because its size exceeds the threshold for normal priority mail, the resulting delay notification (which includes the original message) is not delayed.
  • If a Notes® client user sets the Delivery Reports option to None in the Delivery Options dialog box.