This is part 3 of my guide to getting a mail server configured with all the sexy bits to improve deliverability, spam and virus protection.
You can view part 1 here and part 2 here.
The key pair
We need to create a key pair to sign emails with:
.. code-block:: bash
openssl genrsa -out private.key 1024 openssl rsa -in private.key -out public.key -pubout -outform PEM sudo mkdir /etc/dk/ sudo cp private.key /etc/dk/dk.key
Now we can move on to DK and DKIM signing, make sure you keep the public key for later.
DKIM
First we’ll need to install an application to sign our emails.
sudo apt-get install dkim-filter
Once installed we need to configure it, open up /etc/default/dkim-filter, modify the file to look like below replacing <DOMAIN> with the domain you want to sign email from.
DAEMON_OPTS="-l -o X-DomainKeys …