Sieve ereject and reject and refuse extensions

The original Sieve specification, RFC 3028, defined the optional " " extension and action as being required to result in a Message Disposition Notification. RFC 5429 redefined " " to allow it to refuse messages during the SMTP transaction (rather than accepting messages and generating back a  separate MDN), and defined the " " action to require messages to be refused during the SMTP transaction. The MTA also supports the nonstandard " " action, capability name " ", which was an earlier draft approach similar to " ": note that " " attempts to do an SMTP level rejection but falls back to an MDN when SMTP level rejection is not feasible (as for instance in the case of a multi-recipient message where not all recipients are to be rejected, or when the  channel option is set), whereas " " will, if SMTP rejection is not feasible, discard messages with forged return-path or fall back to a DSN. The capability name for " " with its original behavior (MDN generation) is " "; the capability name for the " " action and for the updated behavior from the " " action is " ".

Note that " ", as per its design from RFC 5429, is only intended to be made available on ingress MTAs capable of returning an SMTP level error directly to remote systems in other administrative domains; the   MTA option which enables " " availability is on by default, but may (and should) be disabled on "internal" MTA hosts.

When " " support was first added (MS 6.1), " " was only supported in system-level Sieve scripts. That restriction was removed for MS 6.2. Also, prior to Messaging Server 7.0, a " " for any recipient caused an SMTP-level " " for all recipients; as of Messaging Server 7.0, instead " " performs an SMTP-level rejection only if " " applied to all recipients and otherwise falls back to generating an MDN regarding the " " recipient(s). Also as of Messaging Server 7.0, a " " in a more general (e.g., sytem-level) Sieve will override actions taken by more specific (e.g., user-level) Sieves.

Each of " ", " ", and " " takes a single string argument specifying error text to include in the SMTP error or notification message.

Note that ", " ", and " " cannot be combined with anything except " ", " ",  " ", or " ".

Note that any Sieve " " actions in a user-level Sieve script will be automatically cancelled when the overall Sieve verdict is " ", " ", or " " (or " "); but " " action in a system-level Sieve script will, as of Messaging Server 7.0.5, be honored despite the overall verdict, thus making it possible to use " " for some limited administrative auditing purposes.

New in 8.0, the " ", " ", and " " actions will parse any extended SMTP error code (e.g., "5.7.2") that appears at the beginning of the action&#x27;s string argument in any system-level Sieve script, and use it in preference to the default 5.7.1 extended SMTP error code. This feature is not available to user-level Sieve scripts.

See also:
 * enable_sieve_ereject MTA Option
 * Notification message types
 * acceptalladdresses Option
 * Sieve supported extensions
 * Sieve filters