MTA-STS helps domains require TLS for inbound email delivery. Learn how it works and why it improves security.
MTA-STS (Mail Transfer Agent Strict Transport Security) is a policy mechanism that helps domains enforce TLS for inbound mail delivery. It reduces downgrade attacks and misconfigurations.
It works through a DNS record and a hosted policy file. When configured properly, it increases the chance that mail to your domain is delivered over encrypted connections.