Blogs
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DMARC
Why Email Forwarding Breaks DMARC (And What Happens When ARC Goes Away)
When you forward an email, SPF, DKIM, and DMARC often fail — even for legitimate mail. ARC was the fix. Here's what happens now that ARC is being retired, and what replaces it.
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DMARC
Why DMARC Passes for Forwarded Email But Still Fails Alignment - and What ARC Solves
When email gets forwarded, SPF and DKIM still pass — but DMARC fails. Here's why alignment breaks and how ARC (Authenticated Received Chain) fixes it.
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DKIM
Why Third-Party Vendor Emails Bounce from Microsoft 365 Despite SPF and DKIM Being "Configured"
<p>A third-party vendor says their DKIM is configured for your Microsoft 365 domain but Microsoft still reports missing DKIM signatures. Here is why and what to do about it.</p>
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DMARC
Why Email Forwarding Breaks DMARC (And What Happens When ARC Goes Away)
Forwarding email often breaks SPF, DKIM, and DMARC — even for legitimate mail. ARC was the fix for that. Here's what happens now that ARC is being retired, and what replaces it.
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DMARC
What Happens When You Forget to Re-Add DMARC After Changing Email Providers?
Forgot to restore your DMARC record after an email provider migration? Here's what happens to your email deliverability, and how to recover it fast.
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DKIM
What Is DKIM2 and What Changed in the April 2026 Draft?
DKIM2 replaces the single-signature model that breaks on forwarding with a chain-of-custody system where each intermediate server adds its own signature. Here’s what the April 2026 draft changes and what it means for email operators.
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What ingress-nginx End-of-Life Means for Your Email Security (And What to Do Next)
ingress-nginx is archived and the last version embeds a vulnerable NGINX. Here is how to tell if you are affected, which remediation paths exist, and why you need to watch your DNS during the migration.
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DMARC
Why International Mail Fails After Moving to DMARC p=reject
Three reasons international mail starts bouncing after tightening DMARC policy — and how to fix each one.
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SPF
How to Fix "Sender address rejected: need fully-qualified address" in Postfix
Postfix rejects outgoing mail with "Sender address rejected: need fully-qualified address" when the SMTP envelope sender address is unqualified. This guide covers the root causes and tested fixes.
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DMARC
How to Detect Vendor-Compromise Phishing: When Trusted Senders Become Attack Vectors
Vendor-compromise phishing slips past traditional email security because it comes from legitimate infrastructure. Here's how to detect it using DMARC reports and what you can do before it reaches your users.