Section 1.6 Flashcards

1
Q

How many dns root server clusters are there?

A

13

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

TLD

A

Top Level Domain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are examples of some Top Level Domains?

A

.com
.net
.org
.gov
.edu
.(country)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

FQDN

A

Fully Qualified Domain Name

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a Fully Qualified Domain Name?

A

An FQDN has the subdomain/hostname, domain and top level domain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the process of DNS resolution?

A

First, the computer checks its local cache. If not there, then the cache of the DNS resolver like the ISP or Google. If not there, then the TLD server.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What’s the difference between a non-authoritative answer vs an authoritative answer in a DNS lookup?

A

Non-authoritative is cached information, whereas authoritative is directly from the source.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What term determines how often the DNS cache is updated?

A

The Time To Live or TTL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In what increments of time is the domain TTL in?

A

number of seconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Command for simple forward and reverse dns lookup

A

nslookup [domain/IP]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Command for detailed foward dns lookup

A

dig [domain]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Command for detailed reverse dns lookup

A

dig -x [IP]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

NTP

A

Network Time Protocol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What keeps the time across a network synchronized?

A

an NTP server

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What port does the NTP server listen on?

A

UDP 123

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is the level of accuracy rated on an NTP server?

A

by stratum layers. stratum 0, 1, or 2, where lower is more accurate

17
Q

What are the DHCP steps?

A
  1. Discover from client to broadcast
  2. Offer from server to broadcast
  3. Request from client to broadcast
  4. Acknowledgement from server to broadcast
18
Q

How is DHCP handled in large organizations?

A

Routers are configured with DHCP Relay or IP Helper, which forwards DHCP requests to the DHCP server

19
Q

What are 5 components to a DHCP scope?

A

IP range (inclusion and exclusion)
Lease duration
Subnet mask
Default gateway
DNS server

20
Q

How is an IP renewed by the client with a DHCP server?

A

At 50% of the lease time (T1), the client attempts to renew the IP with the original DHCP server

At 87.5% of the lease time (T2), if the lease hasn’t been renewed, the client tries to rebind with any available DHCP server

21
Q

What’s the difference between a forward DNS lookup vs a reverse DNS lookup?

A

A forward lookup searches the domain name

A reverse lookup searches the IP address

22
Q

What is the DNS hierarchy from top-down?

A

Root (.)
TLD (com/org)
SLD (wikipedia/google)
Subdomains (www/mail)

23
Q

SLD

A

Second Level Domain

24
Q

What is a DNS zone transfer and what’s their purpose?

A

They copy a DNS server to secondary servers to provide redundancy

25
Q

What is an A record?
What does it map?

A

IPv4 Address record
Maps a domain name to an IPv4 address

26
Q

What is a AAAA record?
What does it map?

A

IPv6 Address record
Maps a domain name to an IPv6 address

27
Q

What is a CNAME record?
What does it map?

A

Canonical record
Maps domain name to aliases

28
Q

What is an MX record?
What’s its purpose?

A

Mail Exchange record
Tells sender’s mail server where to deliver the message.

29
Q

What is a TXT record?
What’s its purpose?

A

Text record
Stores text for verification and security

30
Q

What is a PTR record?
What does it map?

A

Pointer record
Maps IP address to domain name

31
Q

What is an NS record?
What does it map?

A

Name Server record
Maps domain to authoritative dns server

32
Q

What is an SOA record?
What’s its purpose?

A

Start of Authority record
Contains the DNS zone details

33
Q

What is an SRV record?
What’s its purpose?

A

Service record
Helps clients on network find another service