[Mimedefang] remove_redundant_html > delete_header?

[Joseph Brennan]

You're doing things I don't do, so I can't be specific but as generalizations...

Most of us have Mimedefang run the Spamassassin checks, and so we
don't run the separate Spamassassin daemon.

If you have Mimedefang change the message in any way, you should
remove the DKIM headers.

Since you are checking DKIM with a separate milter, you can configure
Spamassassin not to check it.


Joe Brennan
Columbia University



On Thu, Sep 21, 2017 at 11:50 PM, Michael Fox <news at mefox.org> wrote:
> I’m new to the list so be gentle!
>
> I’m using Postfix with the following milters/filters in this order:
> * pre-queue milters:  opendkim, mimedefang  (I plan to add opendmarc after
> opendkim)
> * post-queue content filter:  amavisd-new (with spamassassin, clamd)
>
> I have an old client that doesn’t understand HTML.  So, I’m using
> remove_redundant_html_parts().  And that works great.  But by changing the
> message, the DKIM-Signature is no longer going to match.  Since OpenDKIM
> runs before MIMEDefang, it is still able to validate the signature.  So far,
> so good.
>
> But amavis/spamassassin runs after mimedefang.   So I’m wondering if I
> should take further action so that spamassassin doesn’t see a mismatched
> signature.
> Specifically:
> If remove_redundant_html_parts() returns true (it removed HTML parts), then
> should I also delete the ‘DKIM-Signature’ header?
> And, if I remove the DKIM-Signature header, should I also remove the
> “Authentication-Results:” header?
> In other words, what’s the best method for keeping all of the players happy?
>
> Any thoughts/wisdom would be helpful.
> Thanks,
> Michael