Using Mailbox Filters

A filter consists of one or more conditional actions to apply to a message. Messaging Server filters are stored on the server and evaluated by the server. They are sometimes called server-side rules (SSR).

You can create channel-level filters and MTA-wide filters to prevent the delivery of unwanted mail. You can also create filter templates and make them available to end users by using Messenger Express. End users use the templates to build personal mailbox filters to prevent delivery of unwanted mail message to their mailboxes. The server applies filters in the following priority. See the Sun Java System Messaging Server 6.3 Administration Guide for more information.

1. Per-user filters

   Per-user filters apply to messages destined for a particular user’s mailbox. You can create filter templates and make them available to end users by using the Messenger Express client. End users use the templates to build personal server filters to manipulate the delivery of mail messages to their mailboxes. The filers reject unwanted messages, redirect mail, filter messages into mailbox folders, and so on.

   If a personal mailbox filter explicitly accepts or rejects a message, then filter processing for that message finishes.

   A filter template generalizes a Sieve script by replacing “hard-coded” elements of the Sieve script with prompts and input fields. A Java servlet is used to parse the Sieve templates and generate the user interface in the browser. When an end user supplies values in the input fields, the servlet takes those values and saves them in a Sieve script in the user’s directory profile entry. The prompts and input fields are presented to the end user through the Messenger Express interface.

   If the recipient user had no mailbox filter, or if the user’s mailbox filter did not explicitly apply to the message in question, Messaging Server next applies the channel-level filter.

2. Channel-level filter

   Channel-level filters apply to each message enqueued to a channel. A typical use for this type of filter is to block messages going through a specific channel.

   To create a channel-level filter, you must write the filter using Sieve. See Chapter 18, Mail Filtering and Access Control, in Sun Java System Messaging Server 6.3 Administration Guide for specific instructions on creating filters with Sieve.

   If the channel-level filter explicitly accepts or rejects a message, then filter processing for that message finishes. Otherwise, Messaging Server next applies the MTA-wide filter, if there is one.

3. MTA-wide filter

   MTA-wide filters apply to all messages enqueued to the MTA. A typical use for this type of filter is to block unsolicited bulk email or other unwanted messages regardless of the messages’ destinations.

   To create an MTA-wide filter, you must write the filter using Sieve. See Chapter 18, Mail Filtering and Access Control, in Sun Java System Messaging Server 6.3 Administration Guide for specific instructions on creating filters with Sieve.

   By default, each user has no mailbox filter. When a user accesses Messenger Express interface to create one or more filters, then their filters are stored in the LDAP Directory.