Question
Which of the following ports is used for secure email?
- A. 25
- B. 110
- C. 143
- D. 587 Correct
Explanation
Port 587 is the mail submission port, where clients send email to their server using STARTTLS to encrypt the session, so it is the secure email port among these options. Port 25 is SMTP relay between mail servers and is not inherently encrypted. Ports 110 (POP3) and 143 (IMAP) are the unencrypted retrieval ports; their TLS-protected counterparts are 995 and 993.
