2.5 – Classes of IP Address

Question 1

IANA

Answer 1

Internet Assigned Number Authority

o IP addresses assigned & allocated
o Allocates to Big ISPs & organizations to YOU
o Allocate addresses in blocks

Question 2

Classful Networking

Answer 2

of Hosts [computers]

Class
1st Octet
Number of Hosts
Subnet Mask

Class A
Class B
Class C

Class D = multicast [NOT assignable]
Class E = research [NOT assignable]

Assign IP address based on blocks

Question 3

Class A

Answer 3

Hosts: 16.7 million

1st Octet: 1–126
Number of Hosts: 16.7 million
Subnet Mask: 255.0.0.0

Question 4

Class B

Answer 4

Hosts: 16.7 million

1st Octet: 128–191
Number of Hosts: 65 thousand
Subnet Mask: 255.255.0.0

Question 5

Class C

Answer 5

1st Octet: 192–223
Number of Hosts: 254
Subnet Mask: 255.255.255.0

Question 6

Subnet Mask

Answer 6

tells the computer how many computers are within that network

looks like an IP address
o Follows same pattern & tells IP address network it’s on

o 21.6.10.4 = Class A
- 1st octet is between 1—126

o 160.10.4.100 = Class B
- 1st octet is between 128—191

o 200.100.200.1 = Class C
- 1st octet is between 192—223

Question 7

Remember Subnet Mask

Answer 7

A = 1st letter = 255.0.0.0

B = 2nd letter = 255.255.0.0

C = 3rd letter = 255.255.255.0