Tag messages with custom headers

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.

Marking mail for what happens next

A header like X-Processed-By: MailPolicyEngine gives downstream systems, an archiving tool, a SIEM, another mail filter, a simple way to know a message already passed through your policy engine. Both the header name and value accept variables, so you can record details such as which rule matched or what the original subject was, rather than a single static tag.

Because it is just another action, you can combine it with any condition, tagging only messages from a specific domain, or only ones that also triggered another rule earlier in the same group.

To learn more visit MSH Postfix Milter website.