IPv4/Subnet Masks and IPv4 Classes

Question 1

How many bits in an IPv4 Address?

Answer 1

32 bits /4 bytes of data

Question 2

How many bits in an IPv6 Address?

Answer 2

128 Bits / 16 bytes of data

Question 3

IP Addresses are expressed with the use what types of numbers?

• IPv4
• IPv6

Answer 3

• Decimal Numbers
• Hexadecimal Numbers

Question 4

An IPv4 IP Address can be divided into 2 parts. What are those parts?

Example: 192.168.1.10

Part 1 = 192.168.1
Part 2 = 10

Answer 4

• Network
• Host

Question 5

What is the purpose of the Subnet mask?

Answer 5

It tells the machine which part of the IP address is the Network and Host portion

Question 6

What would the Subnet mask be for IP 192.168.1.4?

Answer 6

255.255.255.0 (/24)

Question 7

A subnet of 255.255.255.0 is also called a /24 subnet. Why?

Answer 7

/24 comes from the number of consecutive 1’s in the binary format.

Example: 255.255.255.0 in binary is 111111.111111.111111.00000000

Question 8

How many IPv4 Classes exist and what are they?

Answer 8

5 Classes

A, B, C, D, E

Question 9

What determines an IPv4 Class?

Answer 9

The first octet of the IP

Question 10

How does one determine the number of Hosts per Network ID?

Answer 10

Use the subnet Mask and convert to binary.
* 255.0.0.0 = 11111111.00000000.00000000.00000000

• 24 zeros as x

Then apply the formula:
* hosts = 2^(x) - 2

Question 11

Class A Starting and Ending address?

Answer 11

0 to 127

Question 12

Class B Starting and Ending address?

Answer 12

128 to 191

Question 13

Class C Starting and Ending address?

Answer 13

192 to 223

Question 14

Class D Starting and Ending address?

Answer 14

224 to 239

Question 15

Class E Starting and Ending address?

Answer 15

240 to 255

Question 16

What IPv4 Classes can be used for Host Addresses?

Answer 16

Class A, B, C

Question 17

What IPv4 Classes can be used for Multicast?

Answer 17

Class D

Question 18

What IPv4 Classes can be used for Experimental purposes?

Answer 18

Class E

Question 19

In an IPv4 Class A address…
* How many bits are reserved for Network Address?
* How many bits are reserved for the Host Address?
* What is the Subnet Mask?

Answer 19

• 8 bits for Network
• 24 bits for Hosts
• 255.0.0.0

Question 20

In an IPv4 Class B address…

• How many bits are reserved for Network Address?
• How many bits are reserved for the Host Address?
• What is the Subnet Mask?

Answer 20

• 16 bits for Network
• 16 bits for Host
• 255.255.0.0

Question 21

In an IPv4 Class C address…

• How many bits are reserved for Network Address
• How many bits are reserved for the Host Address?
• What is the Subnet Mask?

Answer 21

• 24 bits for Network
• 8 bits for Host
• 255.255.255.0

Question 22

Class A was created for what type of networks?

Answer 22

Small number of Networks, Large number of hosts

Question 23

Class C was created for what type of networks?

Answer 23

Large number of Networks, Small number of hosts

Question 24

Explain Public IP vs Private IP Address

Answer 24

**Public IPs **

• Unique
• Registered and Assigned by ISP
• Assigned to Modems

**Private IPs **

• Used inside a private network
• Not unique and can be reused in different private networks.

Question 25

How do devices with private IPs access the internet?

Answer 25

Via the Router/Modem. Using NAT (Network Address Translation)

Question 26

IPIPA Addresses begin with

Answer 26

192.254.xxx.xxx

Question 27

What are the rules to compressing IPv6 addresses?

Answer 27

1. Leading 0’s can be ommitted
2. 2 Continuous sets of 0’s can be replaced with ::
3. 1 Set of 0’s can be replaced with a single 0

Question 28

What are 2 ways to write an IPv6 Loopback address?

Answer 28

• ::1
• 0:0:0:0:0:0:0:1