Lesson 4.9.4.2

4.9.4.2 Standard application layer protocols Quiz: AQA Computer Science, Unit 9

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.9.4.2, Standard application layer protocols: 20 multiple choice questions for the AQA Computer Science (7517), Unit 9: Fundamentals of communication and networking, written with Revision Ninja.

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The 20 questions

  1. Which application layer protocol is normally used to transfer files from a client to a file server?

    • FTP (File Transfer Protocol)
    • POP3 (Post Office Protocol version 3)
    • HTTP (Hypertext Transfer Protocol)
    • SMTP (Simple Mail Transfer Protocol)

  2. Which protocol does a web browser use to request web pages from a web server?

    • HTTP (Hypertext Transfer Protocol)
    • POP3 (Post Office Protocol version 3)
    • FTP (File Transfer Protocol)
    • SMTP (Simple Mail Transfer Protocol)

  3. Which protocol is used to send an email from a client to an outgoing mail server?

    • SMTP (Simple Mail Transfer Protocol)
    • POP3 (Post Office Protocol version 3)
    • HTTPS (Hypertext Transfer Protocol Secure)
    • FTP (File Transfer Protocol)

  4. Which protocol lets a client download email from a mail server to a local device?

    • HTTP (Hypertext Transfer Protocol)
    • SSH (Secure Shell)
    • POP3 (Post Office Protocol version 3)
    • SMTP (Simple Mail Transfer Protocol), which sends mail from a client to an outgoing mail server.

  5. What is the main difference between HTTPS and HTTP?

    • HTTPS is used only for sending email, while HTTP retrieves web pages.
    • HTTPS uses UDP so that pages load faster than with HTTP.
    • HTTPS stores web pages on the client so that no server is needed.
    • HTTPS encrypts the data exchanged between browser and server, whereas HTTP sends it unencrypted.

  6. What is SSH mainly used for?

    • Secure remote login and running commands on a remote computer over an encrypted connection.
    • Serving web pages in HTML form to browsers over port 80.
    • Downloading email from a server and leaving a copy on it.
    • Sending email between two mail servers in plain text over port 25.

  7. What does anonymous access mean for an FTP server?

    • The server encrypts every file using a private key that belongs to the client.
    • A client can log in without a personal account, typically using the username anonymous.
    • A client can transfer files without making any network connection to the server, using a local copy of the files kept on the same device.
    • Only the server administrator is allowed to upload files to the server.

  8. Which well-known port is conventionally used by an HTTP web server?

    • 21
    • 80
    • 110
    • 25

  9. Which well-known port is conventionally used by SMTP when sending email?

    • 110
    • 22
    • 25
    • 80

  10. Which well-known port is conventionally used by POP3 to retrieve email?

    • 22
    • 110
    • 80
    • 25

  11. What is the role of an email server?

    • It renders web pages for display in a browser window.
    • It assigns IP addresses to devices on a local network.
    • It receives, stores and forwards email, and lets clients send or retrieve messages.
    • It encrypts the contents of files stored on a user's device.

  12. What is the role of a web server?

    • It stores each user's email messages until they are read on a device.
    • It translates domain names into IP addresses for every device on the LAN, and it also stores each user's mailbox on the local disk.
    • It serves web pages, in text form such as HTML, in response to requests from clients.
    • It displays web pages on the user's screen after downloading them.

  13. What is the role of a web browser when it loads a page?

    • It retrieves the page and its resources, such as images, then renders them for display.
    • It assigns the web page a public IP address so that it can be found.
    • It sends email messages on the user's behalf to the mail server.
    • It stores all the web server's files on the user's hard drive permanently.

  14. A student uses SSH to connect to port 80 on a web server and types GET / HTTP/1.1. What is the student doing?

    • Sending an email to the web server's administrator at port 80.
    • Transferring a file to the server using anonymous FTP access.
    • Logging into the server's operating system with an administrator password.
    • Manually sending an HTTP request to ask the web server for its home page.

  15. A student connects to port 25 of a mail server and types SMTP commands. What is the student doing?

    • Downloading all messages from the inbox and deleting them from the server.
    • Running a program on the mail server with administrator rights over SSH.
    • Manually sending the commands a mail client would normally send to submit an email.
    • Requesting the web page that displays the inbox in a browser window.

  16. Which protocol should be used to let staff log in securely to a remote Linux server and run commands?

    • SSH (Secure Shell)
    • HTTP (Hypertext Transfer Protocol)
    • FTP (File Transfer Protocol)
    • POP3 (Post Office Protocol version 3)

  17. A bank website must protect card details sent from the browser to the server. Which protocol should it use?

    • POP3 (Post Office Protocol version 3), which is used to send a message from the client to the outgoing mail server for delivery.
    • FTP with anonymous access enabled
    • HTTP (Hypertext Transfer Protocol)
    • HTTPS (Hypertext Transfer Protocol Secure)

  18. In a typical email exchange, which order of protocols is used when one user sends a message and another later reads it?

    • SMTP to send to the outgoing server, then POP3 to retrieve from the incoming server.
    • POP3 to send to the outgoing server, then SMTP to retrieve from the incoming server, with the messages kept on the sending device.
    • HTTP to send to the outgoing server, then FTP to retrieve from the incoming server.
    • SSH to send to the outgoing server, then SMTP to retrieve from the incoming server.

  19. Why does a web browser often make several requests to load a single web page?

    • The page cannot be stored in a single file, so it is always split into one-byte packets.
    • The HTML refers to other resources, such as images and stylesheets, which the browser must request separately.
    • The server sends each paragraph of text on a separate day to save bandwidth.
    • The browser must send an email to the server for every image it displays on screen.

  20. Why is SSH preferred over sending commands in plain text to a remote server?

    • It forces the remote server to send web pages in HTML form instead of plain text.
    • It keeps a permanent copy of every command on the client so that they can be audited.
    • It reduces the number of TCP connections needed to a single port on the server.
    • Its encrypted connection stops eavesdroppers reading the commands, passwords or output sent across the network.

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