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What is the valid range of a Class A network address?

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  • Last Updated : 05 Jul, 2022
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Let us know what an IP address is first, if you already know, skip this section. 

IP (Internet Protocol): 
It is one of the fundamental protocols inorder to have communications on the Internet. IP describes how the information is addressed, routed by networking devices. An IP address is a number identifying of a computer or another device on the Internet. A simple example could be mailing address.

There are 2 types of IP
1. IPv4 : 32 bit long, Ex:
2. IPv6 : 128 bit long, it is so much longer than IPv4

Example for IPv4 :

1. Dotted Decimal Notation

IPv4: 32 bit long ( Dotted Decimal )

2. Hexadecimal Notation

IPv4: 32 bit long ( Hexadecimal )


  • So, In IPv4 addressing, there are 5 classes to range IP Values : Class A, B, C, D and E.
  • The order of bits in the first octet determine the classes of IP address.
  • IPv4 address is divided into two parts:
    1. Network ID 
    2. Host ID
  • The class can determine the bits used for network ID and host ID.
  • The number of total networks and hosts possible in that particular class can be calculated.
  • Only class A, B and C are commonly used. classes D and E are reserved classes, D for multicast groups and E for future purposes.


  • IP address belonging to class A are assigned to the networks that contain a large number of hosts. Here, class A can support 16 million hosts on 127 networks.
  • Here, the network ID is 8 bits long and the host ID is 24 bits long.
  • IP addresses belonging to class A ranges from 1.x.x.x – 126.x.x.x
  • Default Subnet Mask: 255.x.x.x

Number Of Hosts and Networks:

Number of Hosts: (2^24)-2= 16,777,214 i.e 16 million hosts
Number of Networks: (2^7)-2=126 
Note: Reducing 2 because, and 127.a.b.c are different addresses

>> The range of class A is to

Other classes

Class B: to
Class C: to
Class D: to
Class E: to

My Personal Notes arrow_drop_up
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