SYNOPSIS

CheckMessageId = [true | false]

DESCRIPTION
The CheckMessageId slow.conf configuration item allows the Message-Id: header to be checked for validity.

If this CheckMessageId slow.conf configuration item is declared as true (or if it is omitted which defaults to true), the Milter checks the Message-Id: header (if there is one in the message) is checked for vality. If that header is missing or malformed, the the mid event (as described in the standard event set) is set.

A correctly formed Message-Id: header must be surrounded in angle braces, and must have a user-ish part to the left of an '@' symbol, and a host-ish part to the right an '@' symbol. It is malformed if any part is missing or if the host-ish part lacks a dot.

If this CheckMessageId slow.conf configuration item is false, the above check is skipped.

If you do not control your MX servers, you may get Message-Id: headers that were inserted my your MX servers. In that instance, it will only be possible to check for missing Message-Id: headers when messages are delivered directly to your own mail server.