2.6 DNS

Question 1

What does DNS stand for?

Answer 1

Domain Name System.

Question 2

What is the primary function of DNS?

Answer 2

Translates human-readable domain names into IP addresses.

Question 3

Why is DNS important for internet browsing?

Answer 3

It allows users to access websites using names instead of numerical IP addresses.

Question 4

What is the hierarchical structure of DNS?

Answer 4

Root Level → TLDs → Second-Level Domains → Subdomains → Hosts.

Question 5

What does a TLD (Top-Level Domain) represent?

Answer 5

The last part of a domain name (e.g., .com, .org, .edu, .gov, .uk).

Question 6

What is a second-level domain?

Answer 6

The main domain name (e.g., diontraining in diontraining.com).

Question 7

What is a subdomain?

Answer 7

A prefix to a domain name (e.g., mail.diontraining.com or www.google.com).

Question 8

What is an A record in DNS?

Answer 8

Maps a domain name to an IPv4 address.

Question 9

What is an AAAA record in DNS?

Answer 9

Maps a domain name to an IPv6 address.

Question 10

What is a CNAME record?

Answer 10

An alias that redirects one domain name to another.

Question 11

What is an MX record used for?

Answer 11

Directs email traffic to the correct mail server for a domain.

Question 12

What is a TXT record in DNS?

Answer 12

Stores text-based data, often used for domain verification and email security.

Question 13

What is an NS record?

Answer 13

Identifies the authoritative name server for a domain.

Question 14

What is SPF in DNS?

Answer 14

Sender Policy Framework, used to prevent email spoofing.

Question 15

What is DKIM in DNS?

Answer 15

DomainKeys Identified Mail, which authenticates email using encryption.

Question 16

What is DMARC in DNS?

Answer 16

Domain-Based Message Authentication, Reporting & Conformance, used to enforce SPF and DKIM for email security.

Question 17

What is the difference between recursive and iterative DNS lookups?

Answer 17

Recursive lookups get the full answer from the DNS server, while iterative lookups require the client to query multiple servers.

Question 18

What does TTL (Time to Live) in DNS define?

Answer 18

The amount of time a DNS record is cached before it needs to be refreshed.

Question 19

How does DNS caching help internet performance?

Answer 19

It reduces DNS lookup time and network traffic by storing frequently accessed domain mappings.

Question 20

What happens if a DNS record has a low TTL?

Answer 20

It refreshes more frequently, ensuring up-to-date information but increasing DNS traffic.

Question 21

What does an authoritative DNS server do?

Answer 21

Provides the final answer for a domain’s IP address.

Question 22

What is a DNS resolver?

Answer 22

A server that processes DNS queries and retrieves the required IP addresses.

Question 23

What is a root DNS server?

Answer 23

The top-level DNS server that helps direct queries to the correct TLD name servers.

Question 24

What are common DNS troubleshooting commands?

Answer 24

nslookup, dig, ping, traceroute.