Practical guides and release news for MSH Software email tools: MSH Postfix Milter, Zimbra disclaimers and signatures, Exchange and Postfix autoresponders, attachment filtering and file cleanup. https://www.mshsoftware.com/blog/ en-us Tue, 15 Sep 2026 00:00:00 +0000 After several years of building and supporting mail processing tools for Postfix, we are introducing a solution dedicated to Zimbra Collaboration Suite. MSH Zimbra Rules 1.0 is the first release of a new generation of the product, rebuilt from the ground up on the experience we gained with MSH Postfix Milter and the thousands of messages it processes every day. Tue, 15 Sep 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/09/15/msh-zimbra-rules-1-0-released.html https://www.mshsoftware.com/blog/2026/09/15/msh-zimbra-rules-1-0-released.html MSH Zimbra Rules Signatures and personalized messages are only as good as the data behind them. If job titles, phone numbers and department names are entered by hand, someone forgets to update them after every reorg, promotion or new hire, and the signatures going out the door quietly drift out of date. Mon, 14 Sep 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/09/14/sync-user-attributes-from-your-directory.html https://www.mshsoftware.com/blog/2026/09/14/sync-user-attributes-from-your-directory.html MSH Postfix Milter A disclaimer rule that skips a message, an attachment that should have been stripped but was not, a sender who insists their email never arrived, complaints like these usually land on your desk hours after the message already left the server. Reproducing the conditions in a test tool only gets you a guess at what happened, not a record of it. Mon, 07 Sep 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/09/07/trace-what-happened-to-a-real-message.html https://www.mshsoftware.com/blog/2026/09/07/trace-what-happened-to-a-real-message.html MSH Postfix Milter Policy rules can block, tag and rewrite messages on their own, but sometimes a match needs to trigger something outside the mail flow entirely - a chat notification, a ticket in another system, or a virus scan tool with no native Postfix integration. Building that hook yourself usually means writing and maintaining a custom milter just for one integration. Mon, 31 Aug 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/08/31/run-external-scripts-on-rule-match.html https://www.mshsoftware.com/blog/2026/08/31/run-external-scripts-on-rule-match.html MSH Postfix Milter A rule that looks correct in the editor can still behave differently once mail starts flowing through it. Maybe the condition is narrower than you assumed, maybe another rule in the same group gets there first. Discovering that from a user complaint is the expensive way to find out. Thu, 27 Aug 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/08/27/test-rules-before-real-mail.html https://www.mshsoftware.com/blog/2026/08/27/test-rules-before-real-mail.html MSH Postfix Milter Anyone who has ever set up an autoresponder knows the risk: two auto-replying mailboxes can end up answering each other back and forth indefinitely, and even without a full loop, a busy sender can end up getting the same out-of-office notice a dozen times in one afternoon. Mon, 24 Aug 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/08/24/autoresponder-without-reply-storms.html https://www.mshsoftware.com/blog/2026/08/24/autoresponder-without-reply-storms.html MSH Postfix Milter Removing an attachment outright loses information the recipient might actually need. MSH Postfix Milter’s strip attachments action takes a gentler approach: it removes the attachments from a matching message, saves them to a folder on the mail server, and inserts a template into the body in their place explaining what happened. Mon, 17 Aug 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/08/17/strip-attachments-to-folder.html https://www.mshsoftware.com/blog/2026/08/17/strip-attachments-to-folder.html MSH Postfix Milter Large attachments add up fast across a whole organization’s mailboxes, and asking employees to zip files themselves before sending is the kind of habit that never quite sticks. MSH Postfix Milter’s compress attachments action handles it automatically as messages pass through the server. Mon, 10 Aug 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/08/10/compress-large-attachments.html https://www.mshsoftware.com/blog/2026/08/10/compress-large-attachments.html MSH Postfix Milter Blocking attachments by file extension alone is easy to get around, renaming a file changes nothing about what it actually is. MSH Postfix Milter’s remove attachments by type action instead looks at the real content type of each attachment and strips out anything that matches. Mon, 03 Aug 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/08/03/block-dangerous-attachment-types.html https://www.mshsoftware.com/blog/2026/08/03/block-dangerous-attachment-types.html MSH Postfix Milter Not every piece of information about a message needs to be visible in the body. MSH Postfix Milter’s add header action lets a policy rule attach a custom header, name and value, to any message that matches its conditions, invisibly to the recipient but readable by anything further down the mail pipeline. Mon, 27 Jul 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/07/27/add-custom-headers.html https://www.mshsoftware.com/blog/2026/07/27/add-custom-headers.html MSH Postfix Milter Every so often, a message goes out to a group of recipients who should not see each other’s addresses, a customer announcement, an alumni newsletter, a notification sent to an external mailing list. It only takes one sender forgetting to use Bcc for every address on that list to be exposed to everyone else. Mon, 20 Jul 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/07/20/move-recipients-to-bcc.html https://www.mshsoftware.com/blog/2026/07/20/move-recipients-to-bcc.html MSH Postfix Milter Sometimes the content of a message is fine and only the subject line needs to change. MSH Postfix Milter’s rewrite subject action lets you match part of a subject with a regular expression and replace it with whatever text you need, as messages pass through the milter. Mon, 13 Jul 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/07/13/rewrite-subject-lines.html https://www.mshsoftware.com/blog/2026/07/13/rewrite-subject-lines.html MSH Postfix Milter Blocking a message is not a single action, how you block it changes what happens next on both ends of the connection. MSH Postfix Milter’s block message action gives you four ways to do it, each returning a different response to Postfix during the SMTP transaction. Mon, 06 Jul 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/07/06/block-messages-smtp-codes.html https://www.mshsoftware.com/blog/2026/07/06/block-messages-smtp-codes.html MSH Postfix Milter Plenty of mail rules only make sense for one direction of traffic, a disclaimer belongs on outgoing mail, not on messages two colleagues exchange internally. To make that distinction, MSH Postfix Milter needs to know which domains actually belong to your organization. Mon, 29 Jun 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/06/29/domains-internal-mail.html https://www.mshsoftware.com/blog/2026/06/29/domains-internal-mail.html MSH Postfix Milter Not every mail policy should apply around the clock. MSH Postfix Milter lets you attach a scheduler to any rule, so it is only active during the time windows you define, and does nothing outside of them. Mon, 22 Jun 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/06/22/schedule-rules-by-time.html https://www.mshsoftware.com/blog/2026/06/22/schedule-rules-by-time.html MSH Postfix Milter A rule that applies to every message is rarely what you actually want. MSH Postfix Milter gives every rule type the same rich set of conditions: message direction, sender, recipient, headers, subject or body content, attachment name, type, size and count, message size, and even how many messages a sender or recipient has generated recently. Mon, 15 Jun 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/06/15/conditions-and-exceptions.html https://www.mshsoftware.com/blog/2026/06/15/conditions-and-exceptions.html MSH Postfix Milter Once you have more than a handful of policy rules, a single flat list becomes hard to reason about. MSH Postfix Milter lets you organize rules into named groups, each with its own list of rules and its own logic for what happens next. Mon, 08 Jun 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/06/08/organize-rules-into-groups.html https://www.mshsoftware.com/blog/2026/06/08/organize-rules-into-groups.html MSH Postfix Milter A signature or disclaimer template is only as useful as the data behind it. MSH Postfix Milter resolves per-user attributes, name, title, phone number and other fields, at send time and drops them into the placeholders inside your templates. Mon, 01 Jun 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/06/01/personalize-with-user-attributes.html https://www.mshsoftware.com/blog/2026/06/01/personalize-with-user-attributes.html MSH Postfix Milter Signatures and disclaimers both come from the same place in MSH Postfix Milter: the Templates panel. Instead of pasting HTML into each rule by hand, you design a template once and reuse it across as many signature and disclaimer rules as you need. Mon, 25 May 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/05/25/signature-disclaimer-templates.html https://www.mshsoftware.com/blog/2026/05/25/signature-disclaimer-templates.html MSH Postfix Milter A legal disclaimer rule that simply appends text to every outgoing message works fine for a single email, but on a long back and forth thread the same disclaimer can end up stacked at the bottom three or four times as quoted history builds up underneath it. Mon, 18 May 2026 00:00:00 +0000 https://www.mshsoftware.com/blog/2026/05/18/stop-duplicate-disclaimers.html https://www.mshsoftware.com/blog/2026/05/18/stop-duplicate-disclaimers.html MSH Postfix Milter