Microsoft to block unauthenticated emails from May 2025—get tips on DMARC compliance, domain protection, and avoiding email delivery issues.
Understanding DMARC: What It Is and Why Your Business Needs It
DMARC means Domain-based Message Authentication, Reporting & Conformance. It is a method that stops cybercriminals from copycatting emails from your organisation.
It works alongside there two other protection tools
- SPF this verifies who is allowed to send emails to your domain
- DKIM this ensures the content of the message that is sent from the origin has not been intercepted in delivery.
If these tools are not in place, it is very easy for cybercriminals to send attacks via email, such as phishing.
Microsoft’s enforcement is a welcome step, following the lead of Google and Yahoo in requiring DMARC compliance.
What Could Go Wrong If You Ignore DMARC?
If your domain doesn’t meet Microsoft’s new DMARC requirements, your emails could face serious delivery issues:
- Initially: They may be flagged as spam and sent to junk folders.
- Eventually: They could be blocked altogether.
And it’s not just your marketing emails at risk.
This change could disrupt critical business functions, including:
- Sales outreach and prospecting
- CRM and billing system notifications
- Password reset and account confirmation emails
- Internal communications and calendar invites
- Invoices, quotes, and client-facing documents
Even a single email campaign or automated system sending over 5,000 messages per day can trigger enforcement.
If you use tools like Mailchimp, ActiveCampaign, HubSpot, or even a basic contact form on your website, and those messages fail DMARC checks, Microsoft will block them from reaching inboxes.
Snapchat's Spoofing Scandal: A DMARC Lesson
In 2016, Snapchat experienced a serious email spoofing attack. A cybercriminal posed as the company’s CEO and sent a convincing phishing email to someone in the payroll department. Believing the request was legitimate, the employee shared sensitive payroll data belonging to both current and former staff.
The breach exposed personal information of hundreds and dealt a significant blow to Snapchat’s reputation.
The root of the problem? A lack of DMARC enforcement. Without DMARC, Snapchat’s email system had no way to verify the authenticity of the sender, allowing the spoofed message to slip through. If DMARC had been in place, the fraudulent email could have been flagged or blocked entirely—potentially preventing the breach altogether.
Steps to Take Before May 5, 2025: Ensure Compliance with Microsoft's New Policy
To stay ahead of Microsoft’s upcoming enforcement and keep pace with Google and Yahoo, follow these steps:
- Properly configure SPF and DKIM records
- Publish a DMARC record (start in “monitor” mode)
- Identify all services sending emails on your behalf (CRMs, billing platforms, email marketing tools)
- Monitor DMARC reports to track email authentication success or failure
- Transition to a “quarantine” or “reject” policy when you’re ready to enforce stricter controls
How 101 Data Solutions Can Help Your Organization with DMARC Compliance
As Microsoft and other major email providers begin enforcing stricter email authentication protocols like DMARC, 101 Data Solutions can guide your organization through the entire process, ensuring you’re protected from spoofing attacks and that your emails continue to be delivered successfully.
Here’s how 101 Data Solutions can assist:
- DMARC Implementation & Configuration
We will help you set up SPF, DKIM, and DMARC records properly, ensuring your domain is secure and that emails sent from your domain are authenticated and recognized as legitimate. - Audit Your Current Email Systems
101 Data Solutions will conduct a thorough audit of your existing email systems, identifying all services (such as CRM tools, billing systems, email marketing platforms, etc.) that send emails on your behalf. We’ll ensure these systems are fully compliant with DMARC standards. - Transitioning to Strict Policies
After helping you implement DMARC in “monitor” mode, we’ll assist in analyzing the reports and gradually transitioning to a more restrictive policy—“quarantine” or “reject”—when you’re ready to block fraudulent emails and protect your domain from impersonation. - Ongoing Monitoring & Reporting
Our team provides ongoing monitoring to review the reports generated by DMARC. This ensures that you can track which emails pass or fail, identify potential issues, and fix them proactively. - Training and Best Practices
We provide training sessions for your team to ensure everyone understands the importance of DMARC, how to spot phishing attempts, and best practices for maintaining email security. - Future-Proof Your Organization
By working with 101 Data Solutions, you can stay ahead of the curve, ensuring your organization is always ready for the evolving email security landscape. We keep track of any changes in industry standards and keep your systems up to date with minimal disruption. - At 101 Data Solutions, we’re committed to strengthening our clients’ cybersecurity posture. That’s why we’ve partnered with Sendmarc, a leader in email security, to provide robust DMARC (Domain-based Message Authentication, Reporting & Conformance) solutions. This partnership enables our clients to protect their domains from phishing, spoofing, and impersonation attacks—ensuring safer, trusted communication across every inbox.
