Messaging Server provides mail filters on a per-user, per-channel, and system-wide basis. Per-user channels can be managed from any web browser in Messenger Express. Using these filters, users can control what mail messages are delivered to their mailbox. For example, a user tired of “make money fast” UBE can specify that any message with such a subject be rejected. Mail filtering in Messaging Server is based on the Sieve filtering language (RFCs 3028 and 3685) developed by the Internet Engineering Task Force (IETF).
See Using Mailbox Filters for more information.
You can also implement content-based filtering or virus scanning through the use of third-party content filtering software, such as Brightmail and SpamAssassin. See Anti-Spam and Anti-Virus Considerations for more information.