What Is DMARC and Why Does Your Business Need It?
If you've ever received an email that looked like it came from a trusted company, only to discover it was a scam, you've seen the problem DMARC was designed to solve.
Email remains one of the most common ways cyber criminals target businesses. In many cases, attackers don't need to hack your systems at all. They simply pretend to be someone else.
They might impersonate:
Your company
Your managing director
A supplier
A customer
Your bank
To the recipient, the email looks genuine.
That's where DMARC comes in.
What Does DMARC Stand For?
DMARC stands for: Domain-based Message Authentication, Reporting and Conformance
It's an email security standard that helps protect your domain from being used by cyber criminals to send fraudulent emails.
In simple terms, DMARC tells receiving email servers: "If an email claims to come from our business, here's how to verify it's genuine and here's what to do if it isn't."
Without DMARC, it is far easier for attackers to impersonate your organisation.
Why Is Email Spoofing Such a Problem?
Imagine receiving an email that appears to come from:
accounts@yourcompany.co.uk
The message requests an urgent payment or asks a supplier to update bank details.
The recipient recognises your company name and assumes the email is legitimate.
Unfortunately, the email may have been sent by a cyber criminal on the other side of the world.
This is known as email spoofing.
The attacker isn't hacking your mailbox. They're simply pretending to be you.
Without proper email authentication, many email systems struggle to distinguish between genuine emails and fake ones.
How DMARC Works
DMARC doesn't work alone.
It relies on two other email security technologies:
SPF (Sender Policy Framework)
SPF identifies which mail servers are authorised to send email on behalf of your domain.
DKIM (DomainKeys Identified Mail)
DKIM adds a digital signature to emails, helping prove that messages haven't been altered during transit.
DMARC
DMARC sits on top of SPF and DKIM.
It checks whether incoming emails pass these authentication checks and tells receiving email systems what action to take if they fail.
Think of it like a security guard checking identification before allowing someone into a building.
What Happens Without DMARC?
Without DMARC protection:
Criminals can spoof your domain
Customers may receive fraudulent emails appearing to come from you
Suppliers could be targeted with fake payment requests
Your brand reputation can suffer
Email deliverability may be reduced
Legitimate emails are more likely to be flagged as suspicious
Many businesses don't realise they have a problem until a customer calls asking: "Did you really send this email?"
The Three DMARC Policies
DMARC can be configured in three stages.
None
The receiving server monitors emails and reports activity but takes no action.
This is often used when businesses first implement DMARC to understand what is happening.
Quarantine
Emails that fail authentication checks are sent to spam or junk folders.
This provides additional protection while still allowing monitoring.
Reject
Unauthorised emails are rejected completely.
This is the strongest level of protection and prevents fraudulent emails from reaching recipients.
Most organisations aim to reach a reject policy once their email environment has been fully validated.
A Real-World Example
Imagine your business uses Microsoft 365.
A cyber criminal sends an email pretending to be:
director@yourbusiness.co.uk
The email asks a supplier to update payment details for future invoices.
Without DMARC, that email may be delivered successfully.
With a properly configured DMARC policy, the recipient's email server can identify that the message did not originate from an approved source and reject it before it reaches the inbox.
The attack fails before anyone has a chance to click, reply, or transfer money.
Why DMARC Matters More Than Ever
Cyber criminals are becoming increasingly sophisticated.
Many phishing attacks no longer contain spelling mistakes, suspicious links, or obvious warning signs.
Instead, they rely on trust.
If an attacker can successfully impersonate your business, they already have a significant advantage.
DMARC helps remove that advantage.
It protects:
Your brand reputation
Your customers
Your suppliers
Your employees
Your email deliverability
Most importantly, it reduces the likelihood of your organisation being used as part of a phishing attack.
How Do You Know If DMARC Is Configured Correctly?
This is where many businesses struggle.
Modern organisations often send email from multiple platforms, including:
Microsoft 365
CRM systems
Marketing platforms
Website forms
Accounting software
Third-party applications
If DMARC isn't configured correctly, legitimate emails can be affected.
That's why implementation should always be carefully planned, monitored, and tested.
Email Security Starts with Visibility
DMARC is one of the most effective ways to protect your business from email impersonation attacks.
Yet many organisations either don't have it configured or have only partially implemented it.
As cyber threats continue to evolve, email authentication is no longer optional. It's becoming a fundamental part of doing business securely.
Unsure Whether Your Domain Is Protected?
At Sunrise Technologies, we help businesses assess their Microsoft 365 security, email authentication, and cybersecurity posture.
Our team can review your SPF, DKIM, and DMARC configuration to identify vulnerabilities and help ensure your domain is protected from impersonation attacks before they become a problem.