IPA IP 2023 Question 68
A question IPA Japan published in 令和5年度 ITパスポート試験 公開問題 問68, translated into English. ITPEC is based on the same exams.
Same question on ITPEC: Apr 2026 Q33
On computers on the Internet, a range of application programs such as web and e-mail run, and a communications protocol in the application layer that corresponds to each application program is used. Which of the following is a communications protocol that is in a lower layer than these communications protocols, and is commonly used to implement basic communications functions?
Explanation
TCP/IP — the protocols below the application layer that carry the data for web, e-mail and every other application.
Each application has its own application-layer protocol: HTTP for the web, SMTP and POP for e-mail, FTP for file transfer. They all rely on the same lower layers: TCP (transport layer) delivers the data reliably and in order between the two programs, and IP (Internet layer) addresses the packets and routes them between networks. TCP/IP names this common foundation, and the whole suite, of the Internet.
Answer (d)
Why not others:
- •(a) FTP — an application-layer protocol for transferring files
- •(b) POP — an application-layer protocol for receiving e-mail from a mail server
- •(c) SMTP — an application-layer protocol for sending and relaying e-mail
Key rule: Application protocols (HTTP, SMTP, POP, FTP) define a service; they all run on top of TCP (or UDP) and IP, which move the data.
Networks · 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.