What does SMTPS stand for?

• A. Simple Mail Transfer Protocol Secure
• B. Simple Mail Transfer Protocol
• C. Secure Mail Transfer Protocol
• D. Secure Sockets Layer

Answer: (A)

SMTPS stands for Simple Mail Transfer Protocol Secure—the secure version of SMTP that uses TLS/SSL to encrypt the mail in transit. The added "Secure" signals that the connection is encrypted, protecting the contents from eavesdropping and tampering. This is different from plain SMTP, which sends data in plaintext by default. The other options either imply a different naming or refer to the security layer itself (SSL) rather than the mail transfer protocol. In practice, SMTPS often runs with implicit TLS on a dedicated port (commonly 465) or uses STARTTLS on 587 to upgrade a plain SMTP connection to TLS.