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  • The State of Email Security Across the Top Million Domains

    A monthly research project measured DMARC, MTA-STS, DANE, and BIMI adoption across the top one million domains for two months running — here is what the data shows.

    DMARCGuardian Editorial Team · July 11, 2026

  • DMARC

    Why Your Postfix Emails Still Get Rejected by Gmail Even When SPF and DKIM Pass

    SPF and DKIM both pass but your email still fails DMARC. The issue is alignment. Here is what alignment means, why Postfix servers trip it up, and how to fix it.

    DMARCGuardian Editorial Team · July 11, 2026

  • DMARC

    What DMARC, MTA-STS, DANE, and BIMI Adoption Actually Looks Like Across the Top Million Domains

    Measurement data from the top million domains reveals where email security protocols actually stand - and why published adoption numbers often overstate enforcement.

    DMARCGuardian Editorial Team · July 11, 2026

  • DKIM

    DKIM2 and DMARCbis: What the New Standards Change for Email Authentication

    DKIM2 and DMARCbis are incoming standards that will reshape how email authentication works. Here is what each changes, what stays the same, and how to prepare.

    DMARCGuardian Editorial Team · July 11, 2026

  • Deliverability

    How to Find and Fix an Undocumented Mail Relay That Bypasses Gmail Spam Filters

    Gmail is letting spam through from your domain, but your email security setup looks fine. The culprit is usually an undocumented or forgotten internal mail relay forwarding mail through Gmail in a way that bypasses the normal spam filter chain. Here is how to find it and close the gap.

    DMARCGuardian Editorial Team · July 11, 2026

  • Deliverability

    Ghost Send: How M365 URL Decryption Enables OAuth Token Theft

    Ghost Send exploits M365 URL rewriting to trick the security scanner into triggering an OAuth flow that hands tokens to attackers.

    DMARCGuardian Editorial Team · July 10, 2026

  • DMARC

    The Hidden Risks of AI in DMARC Monitoring: What Can Go Wrong

    AI-enabled DMARC tools promise automation and ease, but they introduce specific risks: misconfigured policies, false confidence from summaries, and diagnostic blind spots. Here is what practitioners need to know.

    DMARCGuardian Editorial Team · July 10, 2026

  • DMARC

    How to Find Hidden Exchange Mailbox Forwarding Rules That Evade the Admin Center

    An Exchange 2019 mailbox is forwarding to an external address but nothing shows in EAC or MFCMAPI. This guide gives you a systematic checklist for finding every type of forwarding rule in Exchange Server.

    DMARCGuardian Editorial Team · July 10, 2026

  • DKIM

    DKIM2 and DMARCbis - What Email Authentication's Next Generation Changes

    DKIM2 and DMARCbis are the next generation of email authentication standards. Here is what they change, what problems they solve, and how to start testing them today.

    DMARCGuardian Editorial Team · July 10, 2026

  • DMARC

    How DMARC Reject Policy Silently Blocks Your Own Subdomain Mail (And How to Catch It)

    A DMARC expert explains how p=reject on your root domain silently blocks subdomain mail that lacks its own SPF and aligned DKIM, and how monitoring your DMARC reports is the only way to catch it before users complain.

    DMARCGuardian Editorial Team · July 10, 2026

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