DANE, or DNS-Based Authentication of Named Entities, is a security protocol that is used to help protect against fraudulent SSL/TLS certificates and to improve the security of SSL/TLS connections. It works by using DNS records to bind a domain name to a digital certificate or public key, allowing client systems to verify the authenticity of the certificate and establish a secure connection with the server.
In the context of email, DANE can be used to help secure the transmission of email messages over an SSL/TLS connection. By using DANE, it is possible to help ensure that the SSL/TLS certificate presented by the server is legitimate and has not been tampered with or forged. This helps to protect against man-in-the-middle attacks and other types of email fraud.
To use DANE for email, the server must be configured with an SSL/TLS certificate that is signed by a trusted certificate authority (CA) and published in the domain's DNS records. The client system can then use the DNS records to verify the certificate and establish a secure, encrypted connection with the server.