IPA FE Subject A sample Question 37
A question IPA Japan published in 基本情報技術者試験 科目A サンプル問題 問37, translated into English. ITPEC is based on the same exams.
Same question on ITPEC: Apr 2023 Q45
When a sender from domain A sends an e-mail to a recipient in domain B, which of the following is used by the mail server in domain A for authenticating the sender?
Explanation
SMTP-AUTH — the sender's own mail server checks who is submitting the message before relaying it to domain B.
Sending mail uses SMTP: the sender's mail client submits the message to the domain A server, which relays it to the domain B server. SMTP-AUTH is an SMTP extension in which the client logs in with a user ID and password before the server accepts the message. It stops outsiders from using the server as an open relay for spam.
Answer (d)
Why not others:
- •(a) APOP — a POP3 login that sends a challenge-response digest instead of a plain-text password; it is used when the recipient collects mail, not when the sender sends it
- •(b) POP3S — POP3 over SSL/TLS, which encrypts the recipient's download from the mailbox
- •(c) S/MIME — signs and encrypts the message content end to end; the recipient can verify the signature, but the mail server does not use it to authenticate the sender
Key rule: Authentication on the sending side belongs to SMTP (SMTP-AUTH); authentication on the receiving side belongs to POP3 or IMAP (APOP, POP3S, IMAPS).
Security · AI-written, may contain errors
This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.