Which port is used for secure SMTP submission (SMTPS)?

Which port is used for secure SMTP submission (SMTPS)?

• A. 25
• B. 513
• C. 465
• D. 22

Answer: (C)

SMTPS refers to SMTP with TLS that starts encryption as soon as the connection opens, known as implicit TLS. The port most commonly associated with this secure submission method is 465, where the TLS handshake happens immediately upon connect. The other ports don’t fit that pattern: 25 is standard, unsecured SMTP (though TLS can be used via STARTTLS on some setups); 587 is the submission port that typically uses STARTTLS (explicit TLS) after connecting; 22 is used for SSH, not mail. So port 465 is the one tied to secure SMTP submission.

SMTPS refers to SMTP with TLS that starts encryption as soon as the connection opens, known as implicit TLS. The port most commonly associated with this secure submission method is 465, where the TLS handshake happens immediately upon connect. The other ports don’t fit that pattern: 25 is standard, unsecured SMTP (though TLS can be used via STARTTLS on some setups); 587 is the submission port that typically uses STARTTLS (explicit TLS) after connecting; 22 is used for SSH, not mail. So port 465 is the one tied to secure SMTP submission.