DKIM deep dive: signing, selectors and how verification works

This post is part of the Email Security Foundations series. 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 … Read more

SPF mistakes, troubleshooting, and validation

This post is part of the Email Security Foundations series. 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 … Read more