This is a quick guide to setup DKIM and DMARC records on your postfix-based ubuntu email server. I followed closely a guide from Julian Kunkel and am reproducing many steps from his post here. Despite the fact that he wrote his guide because he found some typos in other guides, his guide also had some.

I’ve been doing work on already working Ubuntu server (xenial, 16.04) with working postfix which I setup using that ArsTechnica article.

In the instructions I will use the placeholder <DOMAIN> for a full qualified domain such as emanat.si. You have to decide about a selector to use which basically provides means to use multiple keys, I use <SELECTOR> as placeholder, in my case, it is “mail”. <EMAIL> is an email where you like to receive errors (in case of DMARC).