Notification messages

The defining characteristic of notification messages is that they have an empty envelope From address. Notification message types gives an overview of the different types of notification messages, those generated by the MTA itself, as well as those notification messages generated externally and  sent to the MTA.

Since notification messages (mostly) are generated automatically, there are some special aspects to them. Notification message generation timing discusses the timing of generation, and for some types of notification messages the delivery scheduling, for notification messages generated by the MTA. The special case of notification messages generated by the Message Store is briefly  discussed in  Message Store notifications that a user himself is overquota; see Message Store documentation for  further details. The format, and potential language selection and customization options, of those notification messages generated by the  MTA are discussed in Notification message format. Special handling of notification messages may sometimes be desirable; Notification message routing discusses the routing of notification messages, and Bounces of spam messages  in particular discusses the case of of spam "blow back" notification messages. Notification message logging discusses special features and factors in MTA message transaction log entries relating to notification messages, and Message size limits and notification messages discusses message size limits in relation to notification messages.

See also:
 * Notification message types
 * Notification message generation timing
 * Message Store notifications that a user himself is overquota
 * Notification message format
 * Notification message routing
 * Bounces of spam messages
 * Notification message logging
 * Message size limits and notification messages
 * Postmaster addresses
 * Sieve setnotify and setreturn extensions
 * NOTIFICATION_LANGUAGE mapping table
 * Notification message MTA options