🚨 Microsoft 365 Will Enforce DMARC Soon – What It Means for Your Business Email

What Is DMARC (and Why Should You Care)?

DMARC stands for Domain-based Message Authentication, Reporting, and Conformance. It’s a security protocol that helps prevent email spoofing, phishing, and other forms of email-based attacks by verifying that messages claiming to come from your domain are actually authorized.

With DMARC in place, receiving mail servers (like Microsoft 365, Gmail, etc.) will check:

• Whether the email really came from your domain (via SPF and DKIM)
• What to do if it fails authentication (reject, quarantine, or allow)

What’s Changing?

Until now, Microsoft has been lenient about how it treats unauthenticated emails. But starting July 2025, Microsoft 365 will begin enforcing DMARC policies, meaning:

• Emails that fail DMARC checks will be rejected or sent to spam, depending on your domain's policy.
• If you haven't published a DMARC record (or if it’s set to “none”), Microsoft may still take action to limit spoofed messages using your domain.

In plain terms: If your domain’s email isn’t properly configured, your messages may not reach their destination.

How This Affects Your Business

If you send emails from your domain (newsletters, invoices, replies, etc.), and you haven’t configured DMARC properly, your customers, suppliers, or staff may not receive them.

Even worse: attackers can spoof your domain more easily if you don’t have these protections in place—putting your brand and customer trust at risk.

What You Should Do Now

Here’s what we recommend at Portal Networks:

✅ Check your DNS settings: Make sure you have valid SPF, DKIM, and DMARC records.

✅ Publish a DMARC record: Even starting with a policy of p=none gives you visibility without blocking emails.

✅ Review all services that send email on your behalf: This includes Microsoft 365, Google Workspace, web servers, marketing platforms (like Mailchimp or HubSpot), etc.

✅ Monitor your DMARC reports: Use a service or tool to view who’s sending email using your domain.

Need Help? That’s What We Do.

At Portal Networks, we offer full support for Microsoft 365, Google Workspace, and custom email hosting—including setting up SPF, DKIM, and DMARC to ensure secure, reliable email delivery.

If you're unsure whether your domain is compliant—or just want to be proactive—reach out today. We’ll audit your current email setup and implement best practices so you’re protected.

📞 519-804-1234
🌐 portalnetworks.ca

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