Secure SMTP using DNS-Based Authentication of Named Entities (DANE) TLSA records.

Secure SMTP using DNS-Based Authentication of Named Entities (DANE) TLSA records. University of Cambridge SMTP has a STARTTLS extension, but (especially in the case of inter- domain mail transfer) it only provides very limited security because it does not specify how to authenticate the server's certificate. This memo specifies how TLSA records in the DNS can be used for proper SMTP server authentication.