Chapter 1

Question 1

What is the primary function of the application layer in networking?

Answer 1

Facilitates user-level communication through protocols for activities like sending emails and browsing the web.

Question 2

What does DNS stand for?

Answer 2

Domain Name System.

Question 3

What is the main purpose of DNS?

Answer 3

Translating domain names to their associated numeric addresses on the internet.

Question 4

What is name resolution in the context of DNS?

Answer 4

Converting names to addresses.

Question 5

What did the internet use for mapping in its early days?

Answer 5

A file containing all the names and addresses of computers.

Question 6

What are the two main principles behind DNS configuration?

Answer 6

• Local Autonomy
• Redundancy

Question 7

How does DNS operate?

Answer 7

As a distributed database enabling users to query name servers for computer addresses.

Question 8

Describe the hierarchical structure of DNS.

Answer 8

A tree-like structure with the root at the top, top-level domains (TLDs) as children, and further subdomains.

Question 9

What are the three categories of top-level domains (TLDs)?

Answer 9

• Generic TLDs (gtlds)
• Country Code TLDs (cctlds)
• Sponsored TLDs (stlds)

Question 10

What utility allows users to query DNS and perform name resolutions?

Answer 10

nslookup.

Question 11

How many root name servers are there, and what is their significance?

Answer 11

There are 13 root name servers responsible for resolving top-level domains.

Question 12

What is a fully qualified domain name (FQDN)?

Answer 12

A domain name that specifies its exact location in the DNS hierarchy.

Question 13

Fill in the blank: The DNS operates as a _______ database.

Answer 13

distributed.

Question 14

What does the ‘set a’ command do in DNS?

Answer 14

Accesses the ‘set a’ domain.

Question 15

What is the role of a domain registrar?

Answer 15

Responsible for managing the registry and adding/removing domains as needed.

Question 16

What is the significance of the Start of Authority (SOA) record?

Answer 16

Provides details like domain name, server name, and contact email.

Question 17

What does the TTL in a zone file represent?

Answer 17

Time to live; defines how long other servers can cache zone file entries.

Question 18

What is an Access Control List (ACL) in the context of DNS?

Answer 18

Configuration that defines which sources can query the name server.

Question 19

True or False: Country code top-level domains are administered by designated authorities.

Answer 19

True.

Question 20

What is the purpose of the WHOIS command?

Answer 20

To retrieve information about domain ownership and IP allocation.

Question 21

What does the MX entry in a zone file designate?

Answer 21

The mail server for the local domain.

Question 22

What is domain name hacking?

Answer 22

Crafting domains to mimic other terms or brands, often with misleading intentions.

Question 23

What is the role of ZADNA in South Africa?

Answer 23

Administers the country code top-level domains like ‘.za’.

Question 24

List some popular DNS services.

Answer 24

• Google’s DNS Service (8.8.8.8)
• Cloudflare’s DNS Service (1.1.1.1)
• OpenDNS (opendns.com)

Question 25

What is the importance of DNS caching?

Answer 25

Reduces the frequency of root server queries and expedites the resolution process.

Question 26

What does the CNAME entry in a zone file do?

Answer 26

Defines synonyms for a domain.

Question 27

What does a negative response in DNS indicate?

Answer 27

That a name does not exist in the domain.

Question 28

What is the purpose of the nslookup command's 'A' record type?

Answer 28

To refine the search to the specific address record.

Question 29

What is the significance of the serial number in an SOA record?

Answer 29

Ensures version control and sync between name servers.

Question 30

What are specialized domains for academia and government in South Africa?

Answer 30

* ac.za (academic institutions) * gov.za (government entities)

Question 31

Fill in the blank: Domain name _______ entails crafting domains to mimic other terms.

Answer 31

hacking.

Question 32

What foundational role does DNS play in the internet?

Answer 32

DNS is the foundation of the internet, essential for achieving its current heights.

Question 33

How does DNS contribute to the internet's design goals?

Answer 33

DNS illustrates technical operation, local autonomy, and redundancy.

Question 34

What is the concept of delegation in DNS?

Answer 34

Delegation is a mechanism for adding subdomains.

Question 35

What role does a registrar play in DNS?

Answer 35

A registrar adds names to a registry, contingent upon fulfilling necessary requirements.

Question 36

What must be configured initially when setting up a domain name?

Answer 36

Zone files and name services.

Question 37

What influences the acceptability of specific domain names?

Answer 37

Controlling authorities and their policies.

Question 38

What is the case of Zetna in South Africa related to?

Answer 38

Zetna is an authority that decides on introducing second-level domains.

Question 39

How do policies for registering names in the DNS vary?

Answer 39

Policies differ across countries, highlighting varying conventions.

Question 40

What legal challenge did Mr. Nissan face with the domain nissan.com?

Answer 40

Mr. Nissan faced challenges from the giant motor manufacturer with the same name.

Question 41

What major topics in DNS were explored in the presentation?

Answer 41

Technical, operational, and regulatory aspects of the Domain Name System.

Question 42

What does the presentation invite viewers to do after discussing DNS?

Answer 42

It invites further exploration into its various facets.