Overview
PureMessage is an email-filtering program
that analyzes email messages at the network gateway. PureMessage checks messages for characteristics
that indicate "spam" (unsolicited bulk email), scans messages for viruses in
conjunction with Sophos Anti-Virus,
and can also check messages to ensure that corporate email adheres to an
organization's communication policy.
PureMessage processes mail in three main steps. (Functionality may vary, depending on
the configuration.)
- The mail server passes a message to PureMessage: The mail server
(sendmail, Postfix, JSMS) passes email to PureMessage via PureMessage's "Milter" service.
- PureMessage applies the policy filter
to the message: The policy script contains tests that check for viruses,
spam indicators, or other message characteristics. The tests have associated
actions that determine what happens to the message if the test returns true.
Available actions include:
- Delivery: Delivery actions can be configured to either deliver
the message to the original recipient, redirect the message to other
recipients, or remove and add recipients. The policy script can be
configured to alter the original message, for example, by altering the
subject line or adding a message header.
- Quarantine: The policy script can be configured to quarantine the
message if certain conditions are met (such as triggering a sufficient
number of anti-spam rules). Quarantined messages are copied to the
quarantine directory. Optionally, the original recipient may be notified
that the message was quarantined via a quarantine digest.
- Quarantined messages are administered: End users can release desired
messages from the quarantine by responding to quarantine digests or via the End
User Web Interface (EUWI). Other messages are automatically archived or deleted
from the quarantine using the pmx-qexpire program, which is
configured by default during the installation to run as a scheduled job.
This document provides an overview of PureMessage. It introduces the major components
of a PureMessage installation and explains
how they work together to keep networks spam-free. For details about installing
PureMessage, see the "Installation
Guide". For complete operation and configuration instructions, see the
Manager Reference and the Administrator's
Reference.