DNS

Question 1

A Record

Answer 1

an address record, maps a hostname to an IPv4 address

Question 2

AAAA

Answer 2

IPv6 address, maps a hostname to an IPv6 addres

Question 3

CNAME

Answer 3

canonical name record, alias of an existing record allowing multiple DNS records to map to the same IP address

Question 4

MX

Answer 4

mail exchange record, maps a domain name to an email server for that domain

Question 5

NS

Answer 5

delegates a DNS zone to use the given authoritative name servers

Question 6

PTR

Answer 6

Pointer record, points to a canonical name
commonly used when performing reverse DNS lookup, which is a process used to determine what domain name is associated with a known IP address

Question 7

SOA

Answer 7

Start of authority record, provides alternative information about a DNS zone, such as email contact information for the zones admin, zones primary name server, and various refresh timers

Question 8

SRV

Answer 8

generalized service location record, used for newer protocols instead of creating protocol specific records such as MX

Question 9

TXT

Answer 9

orginally for arbitrary human readable text in a DNS record, carries machine readable data, such as opportunistic encryption, Sender Policy Framework (SPF), or DomainKeys Identified Email (DKIM)