DNS

Email Security Foundations #05 – DKIM deep dive: signing, selectors and how verification works

This post is part of the Email Security Foundations series on MSDigest.net. What DKIM actually does DKIM stands for DomainKeys Identified Mail. Where SPF checks where a message came from, DKIM proves that the message hasn’t been changed while it was in transit. When you send an email, your mail server adds a cryptographic signature to the message. When the receiving server gets it, it looks up your public key in DNS and uses that …

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Email Security Foundations #04: SPF mistakes, troubleshooting, and validation

This post is part of the Email Security Foundations series on MSDigest.net. The mistakes that break SPF quietly SPF usually does not fail in loud or obvious ways. Mail does not bounce with a helpful error message. It just gets filtered, delayed, or rejected somewhere else. You only find out when someone eventually asks, “Did you get my email?” These are the mistakes I see most often, and how to fix them. Multiple SPF records …

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