> On 05-23-2022 3:36 pm, James Feeney wrote:
> Reading at http://www.postfix.org/MILTER_README.html, and wondering what
> results from Postfix interacting with multiple milters, we see, paraphrasing,
> in
> part:
>
> 1) There can be more than one Milter application.
> 2) Milters "are applied in the order [as] specified".
> 3) "The first Milter application that rejects a command will override the
> responses from other Milter
> applications."
>
> Questions:
> What is the meaning of the phrase "rejects a command"?
> What is the meaning of the phrase "override the responses"?
> What is the meaning of the phrase "in the order specified"?
In the simplest terms;
For example you have a dmarc and dkim milter. In config you list in what order
they run, the dkim first or the dmarc first.
smtpd_milters = unix:/var/run/opendkim/opendkim.sock
unix:/var/run/opendmarc/opendmarc.sock
That is what it means by in the order specified, in the above example dkim runs
first before dmarc.
Rejects a command is if something in that milter returns a reject response code
like 4xx or 5xx. If dkim runs first before dmarc, and dkim issues a 5xx reject
causing the email to be rejected by postfix, then that's it, postfix isn't
going to bother running dmarc next, whats the point, the email is being
rejected. That is what it means by over riding responses. It makes no
difference what dmarc would have said because dkim already rejected the mail.
dkim overrides any acceptance dmarc would have done.
