6 Application Protocols and Network Services Free Online FlashCards

What does DNS do?

DNS translates human-readable domain names into information computers use to locate network services.

What happens when a DNS resolver has no cached answer?

If a resolver lacks an answer in its cache, recursive resolution consults DNS servers until it obtains a result or an error.

What does a DNS record’s TTL control?

A record’s time to live (TTL) limits how long its cached answer is retained.

What do DNS A and AAAA records identify?

A records provide IPv4 addresses; AAAA records provide IPv6 addresses.

What is the purpose of a DNS CNAME record?

A CNAME record identifies an alias for a domain name.

How do MX records help deliver email?

MX records identify mail-exchange servers. A mail system checks a recipient domain’s MX records to determine where to deliver a message.

How does HTTP exchange information between a client and server?

HTTP is a client–server request-and-response protocol: the client requests a resource, and the server responds with a status code and often content.

What are GET and POST commonly used for?

A browser can use GET to retrieve a page, while a web application can use POST to submit information.

What does HTTPS protect, and what does it not guarantee?

HTTPS is HTTP over a secure connection. TLS helps protect data in transit and authenticate the server, but does not prove a site is trustworthy or its content safe.

What role does SMTP play in email?

SMTP transfers outgoing email between a mail client and a submission server, and between mail servers.

What does IMAP let an email client do?

IMAP lets a client access and manage messages and folders stored on a mail server, supporting synchronization across devices.

What is POP3’s main role, compared with IMAP?

POP3 lets a client retrieve messages from a mail server; its capabilities differ from IMAP’s server-side mailbox and folder management.