This post is part of the Email Security Foundations series on MSDigest.net. Rotating DKIM keys Key rotation is good practice. If a private key is ever compromised, rotating limits how long an attacker can use it. Exchange Online makes this easy. How to connect to Exchange Online using PowerShell to rotate the DKIM Keys. After … Read more
Microsoft published a set of reference architecture diagrams for Purview. If you work with M365 data protection, they’re worth reading. There are 11 diagrams, from the Microsoft Purview Customer Excellence Engineering team, covering the full stack: They’re reference flows, not implementation guides. They won’t tell you how to build a policy, but they help you … Read more
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 … Read more
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 … Read more
If you run an on-premises Exchange Server or any Windows-based SMTP relay that sends mail to or receives mail from Exchange Online, then you might have a hard deadline coming up: March 22, 2026. Miss it, and you can risk breaking your mail flow, if the Root Certificates used by Exchange is not updated. What … Read more