In this post i will capture the installation of opendmarc and how its configure alongside Opendkim.
Configure systemd service file
The specific changes here are lines #9 EnvironmentFile #13 -p $SOCKET
Opendmarc Config file
Modify Postfix milters
If you are running both opendkim and opendmarc your milters will look like this:
Restart the service
Now go modify your DNS, adding a TXT record ‘_dmarc‘with the value ‘v=DMARC1; p=none; rua=mailto:firstname.lastname@example.org‘
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’.