An Overview of DNS - CompTIA Network+ N10-009 - 3.4

Question 1

What does DNS do

Answer 1

Translate FQDNs into computer readable IP addresses. Expand on this.

Question 2

How many root dns server clusters

Answer 2

13 (over 1000 actual servers)

Question 3

gTLDs

Answer 3

hundreds of generic top level domain - .com, .org, .net

Question 4

ccTLD

Answer 4

over 275 Country code top level domains - .us, .ca, .uk

Question 5

DNS is a service used where?

Answer 5

internet, AD and application access

Question 6

How many DNS servers in an organization

Answer 6

Usually two. Very important there’s redundancy.

Question 7

What are the two main DNS servers

Answer 7

Primary - Contains all of the zone info for domain
changes and updates are made to primary server
Secondary - Zone info is read only. Zone transfers are pushed from the primary DNS server. Anything we get from this server was first configured on primary DNS server.

Question 8

Local Name Resolution

Answer 8

Stores a name info an IP address within the local network. No Need to access the production server. Stored on host file

Question 9

Forward Lookup

Answer 9

Provide server with name and it returns and IP address. (one of the most common uses of DNS server)

Question 10

Reverse DNS

Answer 10

Provide the DNS server a IP address and it returns a name. (works on DIG command. can tell you address of where your DNS server is on in the world.

Question 11

usually when you preform a DNS look up it’s not from the authotitaive DNS server. How do you access the authoriative server?

Answer 11

Find the server with nslookup, then you can talk to it

Question 12

When a DNS resolver retrieves a response from a non-authoritative DNS server, what does this indicate about the information provided in the response?non-authoritate server.

Answer 12

The information is a cached copy retrieved from another authoritative source.

Question 13

TTL on a dns server

Answer 13

how long the authive server will maintane the casche of IP addresses

Question 14

how to use dig to see how long a server will keep it cahce

Answer 14

dig jessebuerhaus.com
returns:
jessebuerhaus.com 300 134.323.34.121
300 ( second )is the amount of time.

Question 15

Recursive DNS queries

Answer 15

Recursive query

Question 16

what populates and cache local DNS server

Answer 16

By storing DNS query results retrieved from authoritative or upstream DNS serversRecursive DNS queries.

Question 17

Recursive DNS query

Answer 17

If we can’t resolve an IP by looking at local name server, we go to the root server, if it doesn’t know it sends you to .com or .org server.

Question 18

DNS is transmitted i

Answer 18

in the clear no built in encryption

Question 19

DNSSEC

Answer 19

Domain Name System Security Extensions
Digitally signed DNS responses. That verifies that the info we are getting is coming from a trusted source.

Question 20

DNS over TLS (DOT)

Answer 20

Sends DNS traffic over TCP/853, encrypts it with TLS/SSL

Question 21

DNS over HTTPS (DoH)

Answer 21

Sends DNS over HTTPS packet, using https TCP/443. Some broswers use DoH by default.

Question 22

In which scenario would a client receive a non-authoritative answer from a DNS server?

Answer 22

b) When the DNS server has the requested record cached but is not the authoritative server for the domain