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Use dkim-proxy

Formerly we would setup dkfilter if your using postfix, and wanted to implement domain keys.  The work on dkfilter has been "superceded" by work on dkim-proxy some time ago, and we find it works well.

The project page is here: http://dkimproxy.sourceforge.net

Brandon's Blog

One of our former staff members has an excellent set of instructions for installing dkim-proxy here:


Editing your DNS Zone records

This is easy to do using your Rimuhosting DNS control panel.  From the control panel, go to "Manage your DNS", if you have more than one domain, select the zone you want to add domain keys to.

In the "Edit" menu, click on "Text (TXT)".  Your current records will be displayed, and beneath that will be a box to add a new record.  We are going to add two records.  A policy and a selector record.

First the policy

In the "Name" field, put:


In the "Value" field put:

t=y; o=~

You can check this record here: http://domainkeys.sourceforge.net/policycheck.html

Your next step is to add the selector record.

In the "Name" field, put:


In the "Value" field you will put something like this:

k=rsa; p=MHwwDQYJK ... OprwIDAQAB; t=y

On Debian

You can install the perl modules using CPAN, or there are RPM and DEB packages as well.  We generally recommend sticking to the distribution packages, to make updating your system easier.  The Centos packages are mentioned on that page. If you are running a Debian based system just run:

apt-get install dkimproxy

It will install the necessary dependencies, generate your keys and even start up the proxy server for you.  You will find your keys in /var/lib/dkimproxy/.  You will need to follow Brandon's guide to setup your DNS records, and double check the configuration Debian installed is what you want.  Check the hostname and selector name match your setup for instance here:


I found that Debian uses "postfix" as the selector name, but we typically use "mail" or "selector1" so normally need to change this:

/etc/dkimproxy# tail -1 /etc/dkimproxy/dkimproxy_out.conf 
selector  postfix

You will find the rest of the instructions, and the bits you need to stick in your master.cf in: /usr/share/doc/dkimproxy/README.Debian.gz

There are also some alternative configuration if your using amavisd-new or another content filter.


Then to verify it's all working correctly use Brandon's validator:


Or Jason's at the bottom of this page:


(you did read through this page right?)

Also sending a message to a yahoo account and checking the headers is a good test.

More information and specifications on Domain Keys here: http://www.dkim.org/

Using JavaMail?

Now change the default port JavaMail is sending on from 25, to 587 to sign outgoing messages.  i.e. if your Java app is sending out automated emails to your site's users.