IP Class Checker: What is IP Address Classes?

IP Class Checker

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What is IP Address Classes?

In the early days of the Internet, IP address classes were used to categories and allot IP addresses based on network size. Class A, Class B, Class C, Class D, and Class E IP address classes aided in the management and organization of IP address allocation. The idea of IP address classes, however, became less important with the advent of classless inter-domain routing (CIDR). Understanding IP address classes, on the other hand, can reveal insights into the history of IP addressing. Here's a quick rundown of the IP address classes:

Class A IP Address:

Class A addresses were used in large networks. The first octet (the first 8 bits) of a Class A address was reserved for network identification, with the next three octets available to hosts. Class A addresses have a range of 1.0.0.0 to 126.255.255.255.

Class B IP Address: 

Class B addresses were used for medium-sized networks. The first two octets of a Class B address identified the network, and the remaining two octets were used for hosts. The range of Class B addresses is from 128.0.0.0 to 191.255.255.255.

 

Class C IP Address: 

Smaller networks were given Class C addresses. The network was identifiable by the first three octets, and the final octet was reserved for hosts. Class C addresses have a range of 192.0.0.0 to 223.255.255.255.

Class D IP Address: 

Multicasting, a technique for simultaneously delivering IP packets to a number of hosts, is reserved for class D addresses. This class's addresses fall between 224.0.0.0 to 239.255.255.255. Applications like video streaming, internet gaming, and the sharing of multimedia all employ class D addresses.

Class E IP Address: 

For experimental and research purposes, Class E addresses are set aside. This class's addresses fall between 240.0.0.0 to 255.255.255.255. Class E addresses are now primarily unallocated because they weren't created for widespread use.

It's crucial to remember that the rigid distinctions between IP address classes have diminished with the implementation of CIDR. By employing variable-length subnet masks (VLSM) as opposed to the fixed network/host boundaries established by IP address classes, CIDR enables more flexible IP address allocation. This enables better address distribution to networks of varying sizes and more effective use of IP address space.

Understanding the concept of IP address classes can provide a historical context and foundational knowledge about IP addressing, but for modern networking purposes, CIDR is the prevailing method for IP address allocation and management.