Ready for Microsoft’s new high-volumesender requirements?

In under one minute, Red Sift’s free Investigate tool can determine if your email setup is ready for Microsoft’s new high-volume sender requirements.

Check your readiness now

The business impacts of poor email deliverability

Following Google and Yahoo’s 2024 rollout of bulk sender requirements, Microsoft is now introducing its own email authentication rules for high-volume senders targeting Outlook.com domains. From May 5, 2025, businesses sending more than 5,000 emails a day must comply—or risk having messages throttled, sent to spam, or blocked entirely.

$1M

Additional revenue for every 1% increase in open rates seen by a Red Sift customer.

Breaking down Investigate’s comprehensive check

Red Sift Investigate is the only free tool that checks if your organization is ready for the new bulk sender requirements from Google and Yahoo—already in effect—and Microsoft, rolling out from May 5, 2025.

Validate your implementation of SPF and DKIM

Check that you have defined and implemented valid SPF and DKIM records. SPF and DKIM are email security protocols that, together with DMARC, ensure that no one can send emails from your domain on your behalf.

Confirm SPF or DKIM alignment

Confirm that the domain in your From: header is aligned with either the SPF domain or the DKIM domain to pass DMARC alignment. Verify whether the policy is relaxed or strict.

Verify your DMARC policy

Ensure you have a valid DMARC record with at least a policy of p=none. DMARC is a protocol that stops fraudsters from impersonating your domain.

Use a TLS connection for transmitting email

Check that you are using a TLS connection to send mail. TLS encrypts the communications between two points to ensure messages cannot be read in transit.

Ensure you have valid forward and reverse DNS (FCrDNS)

Make sure that your sending IP address matches the IP address of the hostname specified in the Pointer (PTR) record. This proves that your IP address is using a sending domain that you own.

Set up one-click unsubscribe

Make sure it’s easy for your recipients to opt out of receiving your emails by implementing one-click unsubscribe.

Keep your spam rate low

Microsoft, Google, and Yahoo require spam rates to be below 0.3%. To check your rates, consult Microsoft’s Sender Support, Google's Postmaster Tools, or Yahoo's Complaint Feedback Loop program.

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Trusted by the best security leaders in the business

Pipedrive
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“Thanks to Investigate we were able to fully configure our sending services without any doubt or hesitation about the DNS changes we made. It clearly highlighted everything that required our attention.”

Martin Leppik Pipedrive
Martin Leppik
Cyber Security Analyst
Pipedrive

“Thanks to Investigate we were able to fully configure our sending services without any doubt or hesitation about the DNS changes we made. It clearly highlighted everything that required our attention.”

Martin Leppik Pipedrive
Martin Leppik
Cyber Security Analyst

What makes Red Sift Investigate different?

Red Sift Investigate takes a fundamentally different approach to make sure your organization won't have problems with spam or deliverability when the new requirements take effect. 

Go deeper than looking at DNS records

Only a few of Microsoft, Google, and Yahoo’s requirements can be checked by looking at DNS records, all others depend on dynamically investigating an actual email-sending service.

Test your actual email sending service

By dynamically testing your specific email-sending service, Investigate can ensure that FCrDNS is configured correctly, that there is DKIM or SPF alignment and that the DKIM key is valid.

Surface all the information in one place

After sending an email to Investigate, your results will be revealed in a clear dashboard. For any issues, you will see actionable steps and guidance.

Check your readiness now

See your errors, then solve them with OnDMARC 

Our award-winning DMARC application, Red Sift OnDMARC, offers a 14-day free trial that allows you to action the changes Microsoft is mandating. Once you’ve used Investigate to check how you stack up with Microsoft’s requirements, sign up for a free OnDMARC trial to become compliant.

Learn More About OnDMARC

Why Red Sift?

Red Sift is a global cybersecurity company with deep roots and expertise in email security. We have enabled 1,000+ organizations, including TUI, Capgemini, Domino’s, ZoomInfo and Wise, to easily, quickly, and safely implement DMARC to proactively protect business email communications with customers, suppliers, and partners.

FAQs

What are the new Microsoft requirements for high-volume senders?

Microsoft’s email sender requirements focus on authenticating your email-sending domain. The core requirements are:

  1. SPF (Sender Policy Framework): Set up SPF for the sending domain and ensure the domain's DNS record accurately lists authorized IP addresses/hosts.
  2. DKIM (DomainKeys Identified Mail): Set up DKIM to validate email integrity and authenticity.
  3. DMARC (Domain-based Message Authentication, Reporting, and Conformance): Publish a DMARC policy for each domain that sends mail with at least a policy of “none” and align with either SPF or DKIM (preferably both).

Microsoft has also recommended best practices for email senders, including: 

  • Use a compliant sender address: Make sure the “From” or “Reply-To” address is valid, matches your actual sending domain, and can receive replies.
  • Include a working unsubscribe link: Always provide a clear, easy way for recipients to opt out—especially for marketing or high-volume emails.
  • Maintain clean mailing lists: Regularly remove invalid or inactive addresses to reduce bounces, spam complaints, and unnecessary sends.
  • Be transparent with recipients: Use honest subject lines, accurate headers, and only contact users who’ve given clear consent to hear from you.
Why are these requirements coming into effect?

Microsoft has united forces with Google and Yahoo to ensure that global inboxes become safer and less spammy. We are thrilled that these three email service providers are advocating for these changes, as strong email authentication has always played a critical role in email-based business operations.

How can I get to DMARC enforcement?

To get to full enforcement, you can sign up for a 14-day free trial of Red Sift OnDMARC's automated DMARC application. Click here to learn more about OnDMARC.