IPv4 Address Classes and Range

Introduction to IPv4 Address

The IPv4 Address is a 32 bit binary numbers. The 32 – bit binary IP Address is represented as 4 octets, each consisting of 8 bits. Each octet is converted to decimal format and separate by dot (.) for example.

Decimal IP address - 192.168.1.1

Binary IP address    - 11000000.10101000.00000001.00000001

Decimal Number - 0 to 255

          0.0.0.0  to 255.255.255.255

Binary Number

00000000. 00000000. 00000000. 00000000

To

11111111. 11111111. 11111111. 11111111

The IPv4 divided into 4 classes - A, B, C, D

IPv4 Classes and Address Range

Class A (1 – 126)

1.0.0.0 to 126.255.255.255

Subnet Mask   - 255.0.0.0

First Network of Class A

1.0.0.0         - Network Address

1.0.0.1

to

1.0.0.254

10.0.0.255 - Broadcast Address 

Last Network of Class A

126.255.255.0       - Network Address

126.255.255.1

to

126.255.255.254

126.255.255.254   - Broadcast Address

Valid Network                        - 126

Valid Host per Network         - (2²⁴ - 2) = 16,777,214        

Class B (128 – 191)

128.0.0.0 to 128.255.255.255

Subnet Mask   - 255.255.0.0

First Network of Class B

128.0.0.0       - Network Address

128.0.0.1

128.0.0.2

128.  . . ..

128.0.0.254

128.0.0.255  - Broadcast Address

Last Network of Class B

191.255.255.0        - Network Address

191.255.255.1

To

191.255.255.254

191.255.255.255    - Broadcast Address

Valid Network                       -> 16382

Valid Host per Network        -> (2¹⁶ - 2) = 65,534         

Class C (192- 223)

192.0.0.0 to 223.255.255.255

Subnet Mask - 255.255.255.0

First Network of Class C

192.0.0.0             - Network Address

192.0.0.1

192.0.0.254

192.0.0.255        - Broadcast Address

Last Network of Class C

223.255.255.0       - Network Address

223.255.255.1

To

223.255.255.254

223.255.255.255  -  Broadcast Address

Valid Network                      -> 2,097,150

Valid Host per Network       -> (2⁸ - 2) = 254        

Class D (224 - 239)

224.0.0.0 to 239.0.0.0

The Class D IP address is Reserve for Multi-casting

Class E (240 - 255)

240.0.0.0 to 255.0.0.0

The Class D IP Address is use for research or development/Experiment

Privet IP address Range in different classes

Class A

10.0.0.0 to 10.255.255.255

Class B

172.16.0.0 to 172.31.255.255

Class C

192.168.0.0 to 192.168.255.255

Loop-back address

127.0.0.0 to 127.255.255.255