DNS

Question 1

Top Level Domain (TLD)

Answer 1

.com .edu .org .net .gov .au .uk

Question 2

A

Answer 2

Address record maps hostname to IPv4 address

Question 3

AAAA

Answer 3

Address record maps hostname to IPv6 address

Question 4

TXT (SPF, DKIM)

Answer 4

Designed to hold human readable code originally ; used now to hold machine readable data such as

• DKIM - DomainKeys Identified Email - digitally sign outgoing mail, validated by mail server
• SPF - Sender Policy Framework - prevent mail spoofing, check if came from authorized host
• opportunistic encryption

Question 5

SRV

Answer 5

Generalized Service location record.; newer protocol that doesn’t require specific profile records like MX, CNAME, etc

Question 6

MX

Answer 6

Mail eXchange record maps domain name to email server

Question 7

CNAME

Answer 7

Canonical Name - alias for existing record (google.com = www.google.com)

Question 8

NS

Answer 8

Denotes the authoritative Name Server for the domain

Question 9

PTR

Answer 9

Pointer Record refers to canonical name ; used for reverse DNS lookup

Question 10

Internal DNS

Answer 10

URL to private IP address lookups, can forward to external DNS

Question 11

External DNS

Answer 11

URL to public IP address lookups

Question 12

3rd Party / Cloud-Hosted DNS

Answer 12

Public DNS such as Google’s 8.8.8.8

Question 13

DNS Hierarchy

Answer 13

breakdown/order of FQDN

Top Level - > Second Level - > Third Level, etc

Question 14

Forward Zone

Answer 14

zone where forward lookup is performed

FQDN -> IP

Question 15

Reverse Zone

Answer 15

zone where reverse lookup is performed

IP -> FQDN

Question 16

FQDN

Answer 16

Fully Qualified Domain Name

Question 17

Second Level Domain

Answer 17

“google” in www.google.com

Question 18

Third Level Domain

Answer 18

hostname of a device or subdomain
“www” in www.google.com is a webserver

“engineering” in www.engineering.university.edu is a subdomain