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Domain Protection: How DMARC, DKIM and SPF Stop Email Spoofing

Secure your email domain with Microsoft 365 domain protection. DMARC, DKIM and SPF prevent phishing, spoofing and unauthorised use of your domain.

Secure365 teamSolid Systems Secure365 guide · 2 min read

What is Domain Protection?

Email is one of the most targeted attack vectors for cybercriminals using sophisticated AI attacks. Business domains are frequently exploited in phishing campaigns, allowing attackers to impersonate companies and deceive customers, employees and partners.

With Secure365 Domain Protection, businesses can lock down their domains, preventing unauthorised use and email-based threats such as spoofing, phishing and business email compromise (BEC).

  • DMARC, DKIM and SPF enforcement to secure outgoing email
  • Protection against email impersonation and domain spoofing
  • Better email deliverability by verifying legitimate senders
The risk

Without strong domain security, businesses risk:

  • Cybercriminals impersonating the company to send fraudulent emails
  • Phishing scams using fake email addresses to steal sensitive information
  • Email security vulnerabilities leading to data breaches

How Domain Protection works

Secure365 builds domain security protocols into Microsoft 365, so only authorised senders can use your domain for email.

  1. 1

    DMARC (Domain-based Message Authentication, Reporting & Conformance)

    What it does
    • Enforces a reject policy to block spoofed emails from using your domain.
    • Reports on authentication failures to support proactive email security.
    • Protects against phishing and business email compromise by rejecting fraudulent messages.
  2. 2

    DKIM (DomainKeys Identified Mail)

    What it does
    • Adds cryptographic signatures to outbound emails to verify message integrity.
    • Confirms that sent messages are authentic and have not been altered in transit.
  3. 3

    SPF (Sender Policy Framework)

    What it does
    • Specifies the mail servers authorised to send email on behalf of your domain.
    • Blocks spoofed messages sent from unauthorised servers to reduce impersonation risk.
  4. 4

    Phishing & spoofing prevention

    What it does
    • Prevents AI-driven spoofing attacks that mimic your domain or trick recipients.
    • Authenticates all email traffic to ensure legitimacy and security.
    • Strengthens your email security posture by combining DMARC, DKIM and SPF.

Key benefits

Domain Protection removes the risk of domain impersonation and email-based attacks, helping your business keep a trusted email reputation.

Prevents business email compromiseStops cybercriminals using your domain for email fraud.
Improves email deliverabilityMakes sure legitimate emails reach the inbox, not the spam folder.
Reduces phishing attacksStrengthens security against fake emails sent to employees and customers.
Enhances Microsoft 365 email securityWorks with Microsoft Defender for Office 365 to prevent email threats.
“Solid Systems is an important part of our business, and we consider them a partner in the success of our operations.”
Gavin Financial Director

Who needs Domain Protection?

  • Businesses sending emails to clients, partners and suppliers
  • Financial institutions and legal firms handling sensitive communications
  • Retail and e-commerce businesses with customer email interactions
  • Healthcare providers protecting patient data and compliance standards

Every organisation that relies on email needs domain protection to prevent fraud and phishing scams.

Your path to protection

  1. 17 daysCyber Security AssessmentAn expert-led assessment of your Microsoft 365 environment and security strategy, benchmarked against security frameworks.
  2. 23 daysSecurity Improvement PlanA tailored plan to strengthen your Microsoft 365 security by addressing weaknesses and underused features, with clear, practical steps that meet industry standards.
  3. 3OngoingImplementationCertified Microsoft IT pros implement your security plan to keep your environment secure, with the option of 24/7 incident response.

Steps 1 and 2 cost nothing. You only commit once you’ve seen the plan.

Written byThe Secure365 team

Certified Microsoft IT pros at Solid Systems who design, run and monitor Secure365 for businesses in the UK and South Africa.

Need help with this?

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