HTTP, FTP, SMTP, POP3 & IMAP

State the purpose of HTTP.

HTTP is used to transfer web pages and other web resources.

A browser requests a web page from a server. Which protocol is used?

HTTP.

Explain how HTTP is used when a browser requests a web page.

The browser sends an HTTP request and the web server sends an HTTP response containing the requested resource.

State the purpose of FTP.

FTP is used to transfer files between computers.

A website administrator uploads files to a web server. Which protocol should be used and why?

FTP, because it is designed for transferring files between a client and server.

State the purpose of SMTP.

SMTP is used to send emails between email clients and mail servers and between mail servers.

Explain how SMTP is used when an email is sent.

The sender's client sends the email to a mail server using SMTP; SMTP can then transfer it between mail servers.

Is SMTP a push or pull protocol?

Push.

State the purpose of POP3.

POP3 is used to retrieve emails from a mail server, usually by downloading them to a device.

Explain what happens when POP3 is used to retrieve an email.

The email is downloaded from the mail server to the user's device and is normally removed from the server.

State the purpose of IMAP.

IMAP is used to access and synchronise emails stored on a mail server.

Why is IMAP suitable for accessing an email account from several devices?

Emails remain on the server, allowing multiple devices to access and synchronise the same mailbox.

Compare POP3 and IMAP.

POP3 normally downloads emails to one device; IMAP keeps emails on the server and synchronises them across devices.

Which protocol is used to retrieve a web page?

HTTP.

Which protocol is used to transfer files?

FTP.

Which protocol is used to send emails?

SMTP.

Which protocol is used to download emails to one device?

POP3.

Which protocol is used to synchronise emails across several devices?

IMAP.

State two Application layer protocols and give an example of data exchange for each.

HTTP — web page request/response; FTP — file transfer.