In this post i will capture the installation of opendmarc and how its configure alongside Opendkim.

Install opendmarc

Configure systemd service file

The specific changes here are lines #9 EnvironmentFile #13 -p $SOCKET

Defaults File

Opendmarc Config file

Modify Postfix milters
If you are running both opendkim and opendmarc your milters will look like this:

Restart the service

DNS

Now go┬ámodify your DNS, adding a TXT record ‘_dmarc‘with the value ‘v=DMARC1; p=none; rua=mailto:postmaster@example.com

When you have validated dmarc is working properly you can change p=none to p=reject

How can you validate it?

There are a number of tools online to help you with this, also you open up a mail in google and click ‘show original’.

screenshot_2016-11-20_12-32-23
 

Enjoy

Other resources
https://www.google.com/search?q=opendkim+setup

https://www.google.com/search?q=opendmarc+setup