dk-filter, postfix, and mailscanner

Jason Ede J.Ede at
Tue Nov 23 11:58:38 GMT 2010

I've been looking at this too and if you've a single instance of postfix then I believe you can't do it as it signs the message before it gets passed to mailscanner and then the mailscanner stuff changes the email invalidating the signature.

The solution is to have multiple instances of postfix. The first instance accepts and scans the email using mailscanner and then the email gets passed to  the second instance which does the signing on the way out.

If you can update to postfix >2.6 then it is much better supported from within postfix and documents how to do it. We're in process of setting up a system that uses multiple instances and once it's all complete I hope to add what we've learnt to the wiki.


> -----Original Message-----
> From: mailscanner-bounces at [mailto:mailscanner-
> bounces at] On Behalf Of Dave Gattis
> Sent: 23 November 2010 11:17
> To: mailscanner at
> Subject: dk-filter, postfix, and mailscanner
> Hello everyone,
> Yahoo is sticking my mail straight in the junk folder, so it looks like
> domainkeys is my only hope.  While I was at it, I also installed dkim, which
> works perfectly.  Domainkeys is set up too but no matter what I do, the test
> always comes back as bad signature.  I've tried installing domainkeys without
> dkim and the test still fails.  Has anyone had any luck with this setup?
> Debian 4.1.2
> Postfix 2.5.5
> Mailscanner 4.81
> DK-Filter 1.0.0
> Thanks!
> Dave
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