FAQ
General questions
What does this application do?
MSH Zimbra Rules allows you to create and manage email processing rules for your Zimbra Collaboration Suite server.
With this application, you can define rules to modify email messages based on various criteria, such as sender, recipient, subject, and more.
You can perform actions like adding signatures and disclaimers, sending automatic replies, stripping attachments, modifying subjects, and other email manipulations.
Which Zimbra versions are supported?
The application works with Zimbra Collaboration Suite installations that use Zimbra's bundled Postfix MTA - the milter is attached to that Postfix instance through Zimbra's standard configuration mechanism.
The application itself runs on Java 21 or newer. See Requirements for details.
Is it a milter?
Yes. The core component is a content milter that connects to Zimbra's bundled Postfix through the standard Postfix milter protocol. It inspects and modifies messages before they enter the mail queue.
Does it work with signed or encrypted messages?
Rules are still evaluated for signed (multipart/signed) and encrypted (multipart/encrypted) messages, but actions that would alter the protected message content - such as adding signatures or disclaimers, or modifying attachments - are automatically skipped so the cryptographic signature or encryption is never broken. The skip is recorded in the message's processing trace.
Can it be tested before buying?
Yes, the application can be tested before purchase. After installation, the application operates in Demo mode by default, allowing you to explore its features without limitations, except that each message subject will be shuffled. To access the full functionality without restrictions, you can obtain a Trial license key valid for 90 days.
What does it mean that the message subject is shuffled?
When the application is in Demo mode, it modifies the subject line of each email message for which rules apply by rearranging the words in a random order.
For messages that do not match any rule, the subject remains unchanged.
Zimbra integration
What does Zimbra's built-in milter do?
Zimbra ships its own separate milter service, toggled by the zimbraMilterServerEnabled server attribute and started with zmmilterctl. It has nothing to do with the MSH Zimbra Rules milter - its only job is enforcing distribution-list access control: it checks whether the sender of a message addressed to a distribution list has been granted the sendToDistList right on that list, and rejects the message if not. When enabled, it listens on inet:localhost:7026 by default.
A distribution list with no explicit sendToDistList grants stays open to all senders whether or not this built-in milter is enabled - restriction only kicks in once you add a grant to a specific list. That is why our Zimbra configuration instructions have you enable it as a workaround for a Zimbra bug, even if you do not use distribution-list restrictions at all: without it, Zimbra can silently wipe the smtpd_milters setting that wires in the MSH Zimbra Rules milter on the next MTA restart or reload.
License
How is the application licensed?
The application is licensed with an annual fee per mail server. Each server running the application requires its own license; there is no per-user or per-mailbox cost.
How much does it cost?
For detailed pricing information, please visit our Pricing page.
What happens when Trial ends?
When the Trial period ends, the application will stop processing rules. It's something different from Demo mode, where the application processes rules but shuffles message subjects. In this mode, messages are not affected by any rule.
To continue using the application without limitations, you will need to purchase a license.
What happens when license expires?
When the license expires, the application will stop processing rules.
To continue using the application without limitations, you will need to renew your license.