What is DMARC?

What is DMARC

DMARC is an important Email Anti-Spam feature. It tells Spam Filters how to react if an Email fails your SPF and DKIM requirements. This in turn makes it much more likely that your authentic emails will land in an Inbox and Spam with your name fraudulently on it will go to the Junk folder.

What you need to do

Log in to the website you use to manage your Company Domain Name (or ask your IT dept to do this step). If you're not sure what I mean by this and don't have an IT dept, this will be your "Domain Registrar" or "the company you pay to own the name of your website and the bit after the @ in your email address". Common UK Registrars include Amazon Web Services, FastHosts, Go Daddy, Unlimited Web Hosting, Wix etc.

Look for a TXT entry in your domain with the name "_dmarc". If this is present already, you should not change this. If there is not one present, the below instructions will tell you how to add the most basic and least restrictive DMARC record, however you should research and consider your needs for the best solution.

Create a new DNS record of type TXT then, to create the most basic DMARC record possible:

In the "name" box, paste: _dmarc
In the "value" box, paste: v=DMARC1; p=none;

And click Save. This basic DMARC policystates you have setup SPF and DKIM but are still testing to make sure you haven't made any mistakes.

A more advanced DMARC record might look more like this:

In the "name" box, paste: _dmarc
In the "value" box, paste: v=DMARC1; p=reject; rua=mailto:dmarc-reporting@YourDomain.co.uk; adkim=s; aspf=s;

This DMARC policy states that if any emails fail your SPF and DKIM checks, they should be rejected as Spam and that whenever this happens, the spam filter should email you to let you know so that you can make sure there aren't any false positives. These "DMARC Report" emails will go to whatever address you type instead of rua=mailto:dmarc-reporting@YourDomain.co.uk. There are lots of services available to process these reports for you and that is something you should consider when you upgrade to a stricter DMARC policy.

These steps will look slightly different on each Registrar's website so I've included a list below of Registrar specific guides. If you get stuck, ask their Support staff for help. The question to ask them is "Please can you help me update my DMARC record?". It is important that you don't make any mistakes in this step. If you're not sure, please ask your Registrar's Support for guidance and for them to double check any changes you make.

Amazon Web Services: Configuring DNS, Resource Record Types

Bluehost Bluerock: Manage DNS Records

Dreamhost: DNS Overview

GoDaddy: Add a TXT Record

Google Domains: DNS Basics

Hostgator: Manage TXT records

Hover: Edit DNS Record

IONOS: Configuring TXT Records

Namecheap: SPF & DKIM

Squarespace: Add TXT Records

Wordpress: Adding Custom DNS Records

Siteground: Create TXT Records