What is MTA-STS (MTA Strict Transport Security)?
MTA-STS is a mechanism that enforces TLS encryption for your email communication. Think of it as HTTP Strict Transport Security (HSTS) for email. By instructing the sending mail server that a secure connection is mandatory, you can effectively mitigate or stop Man-in-the-Middle (MITM) attacks. The official abstract from the RFC puts it best:
Continue reading Securing Mail: A Hands-on Guide to MTA-STS and TLSRPT