Networking Core Protocols

Question 1

At what OSI layer does DNS operate on?

Answer 1

(7) Application layer

Question 2

What is DNS an abbreviation for?

Answer 2

Domain Name System

Question 3

What transport protocols does DNS use?

Answer 3

TCP and UDP

Question 4

What records does DNS have?

Answer 4

A (IPv4), AAAA (IPv6), CNAME (Canonical Name: Domain name to domain name) and MX (MailExchange)

Question 5

What CLI tool can you use to look up the IP of a domain such as www.example.com

Answer 5

nslookup (on both Windows and Linux)

Question 6

[CMD] whois www.JeppeOgFredrika.dk

Answer 6

anvender whois som cmd værktøj til at slå op informationer om domænet jeppeogfredrika.dk

Question 7

How would you via telnet use HTTP to retrieve a file.html from ip 10.44.238.25 on the default http port?

Answer 7

telnet 10.44.238.25 80 (ip port)
GET /file.html HTTP/1.1
Host: anything

Question 8

[Acronym] FTP

Answer 8

File Transfer Protocol

Question 9

What port does FTP listen on by default?

Answer 9

21

Question 10

FTP command to download a file once connected, and location on local machine once downloaded?

Answer 10

“get filename” and will be in the pwd/cd of where the ftp client command was executed

Question 11

[CMD] Connect to an ip via ftp

Answer 11

ftp ip

Question 12

[Acronym] SMTP

Answer 12

Simple Mail Transfer Protocol

Question 13

Default port for Simple Mail Transfer Protocol (SMTP)?

Answer 13

25

Question 14

Which SMTP command indicates that the client will start the contents of the email message?

Answer 14

DATA

Question 15

[SMTP] What does the client send to indicate that the e-mail has been fully entered?

Answer 15

A dot on a new line (“.”)

Question 15

Default port for Post Office Protocol 3? (POP3)

Answer 15

110

Question 15

[Acronym] POP3

Answer 15

Post Office Protocol 3

Question 16

What is POP3 used for?

Answer 16

retrieving e-mails

Question 17

[Acronym] IMAP

Answer 17

Internet Message Access Protocol

Question 18

What is the key features of IMAP in comparison to POP3?

Answer 18

You can access the e-mails from various clients (e.g your laptop & your smartphone) whereas POP3 downloads and deletes the e-mail retrived from a server (resulting in that only one client would be able to consume it)

Question 19

Is asynchronization a key aspect of Internet Message Access Protocol (IMAP)?

Answer 19

No. Synchronization is. Actions like marking emails as read, deleting emails, or organizing them into folders are synchronized across all devices.

Question 20

What is IMAP designed for?

Answer 20

IMAP is designed for accessing and managing emails from multiple devices while keeping them synchronized.

Question 21

What is POP3 designed for?

Answer 21

POP3 is designed for simple retrieval and storage of emails on a single device, with limited support for multi-device access

Question 22

Default port for Internet Message Access Protocol (IMAP)?

Answer 22

143

Question 23

Default port for Domain Name System (DNS)?

Answer 23

53