DNS/life of a packet

Question 1

FQDN

Answer 1

Fully Qualified Domain Name.

Question 2

Basic task of DNS

Answer 2

maps IP addresses to readable, human-friendly and easy to remember

Question 3

What port does DNS use

Answer 3

UDP 53

Question 4

ARP

Answer 4

Used to map the IP address to MAC address.

Question 5

What layer does a ARP request happen?

Answer 5

Layer 2

Question 6

what is destination MAC address fff.ffff.ffff

Answer 6

Layer 2 broadcast address

Question 7

What do switches do with broadcast traffic?

Answer 7

forward it everywhere except the source.

Question 8

what happens if a local DNS server apparatus doesn’t contain the needed record?

Answer 8

It will send the request up the chain until a positive response is received. which gets passed back down.

Question 9

what is a FQDN
www.
google.
com
mean

Answer 9

www. the specified service
google. the local domain
com the top level domain

Question 10

What are the three different levels of DNS servers

Answer 10

Local DNS Server
Top Level Domain (TLD) Server
Root Server
Authoritative
Non-Authoritative

Question 11

What is the local DNS server

Answer 11

The server on the local network that contains the HOSTS files that map FQDN to IP address in the local subdomain

Question 12

A record

Answer 12

Maps hostnames, or FQDNs to their IPv4 address

Question 13

AAA record

Answer 13

Maps the FQDNs to their IPv6 address

Question 14

CNAME Record

Answer 14

Maps canonical (alias) names to hostnames. You can have edc.edu the same as edc.org without issues.

Question 15

PTR Record

Answer 15

Points out to DNS that their is a canonical name.

Question 16

MX recrod

Answer 16

Mail eXchange
Maps to the email server that is specified for a specific domain. Its the record that determines how email travels from sender to recipient.

Question 17

Dynamic DNS (DDNS)

Answer 17

Permits lightweight and immediate updates to a local DNS database. This is very useful when FQDN remains the name. but the I{ address is able to change on a regular basis.

Question 18

DDNS

Answer 18

A method of updating traditional name servers without the intervention of a administrator (no manual editing or inputting of the configuration files is required)
DDNS provider supplies software

Question 19

Flag Field

Answer 19

contains a bit of that specifies whether the DNS message is a query or response

Question 20

Query of question field contains multiple sub-fields. two important ones

Answer 20

Resource name - name we want to lookup

Resource Type - type of record we are looking for

Question 21

what is in a DNS answer field

Answer 21

Resource name
Resource Type
Address

Question 22

when a DNS response message arrives at computer A what does it do first

Answer 22

It first updates its DNS cache.

Question 23

What can a computer do after is updates it cache?

Answer 23

it will can ping

Question 24

Most common type of record

Answer 24

A Record- contains a host address (IP address )

Question 25

most devices maintain a cache of DNS records that have been previously resolved using a DNS query

Answer 25

yes

Question 26

what record DNS record type assigns a secondary name to a database server

Answer 26

CNAME

Question 27

what record DNS record type determines the IP address of a VoIP controller

Answer 27

SRV. Service record. finds a service. System performs a DNS lookup of the service record associated with service

Question 28

what record DNS record type resolves an IPv4 address based on a FQDN

Answer 28

A record. Reverse of PTR record.

Question 29

what record DNS record type validates the digital signature of a email message

Answer 29

TXT record

Question 30

what record DNS record type determines the FQDN of an IP address

Answer 30

PTR. Pointer. reverse of how A record works

Question 31

what record DNS record type locates the email server for a domain

Answer 31

MX. Important for emails.

Question 32

What does DNS do?

Answer 32

Translate human-readable names into computer-readable IP address.

Question 33

Is DNS Hierarchical?

Answer 33

Yes. It follows a path.

Question 34

How many DNS root server clusters are there?

Answer 34

13 | 1000s' of actual servers

Question 35

What is a generic top level domain?

Answer 35

.com .org .net, etc

Question 36

Can country codes be top level domains?

Answer 36

yes, over 275 countries. | .us, .ca. uk etc