IP Class Checker

What is an IP Class?

IP (Internet Protocol) classes came about due to the limited space of a 32-bit IPV4 address. Given the limited number of available address IP classes were introduced to prevent waste. Especially in larger networks comprising thousands of connected devices. IP classes are used for allocating IP addresses to systems/devices that connect to a network. There are five classes of IP: A, B, C, D and E. Each class has different components of specific ranges and is used for different scenarios.

Class A addresses the first Octet is used as the network id. Class A is used in large networks such as large corporate entities or organisations. These networks can comprise up to 16 million hosts. But there can be only 126 class A networks on the whole internet. The range of a class A starts at 1.0.0.0 all the way up to 126.0.0.0. That said only 40 of class A addresses are allocated to 40 companies. The remaining 86 classes are used by organisations such as the Internet Assigned Numbers Authority (IANA). These organisations assign IP addresses across the regions Asia, Europe, North America, South America and Australia.

Class B addresses the first two octets is used to indicate the network id. Class B is used in medium sized networks. Class B are reserved for Hospitals, Universities and other medium sized organisations using Class B addresses. Class B addresses start from 128.0.0.0 to 191.0.0.0. Class B networks can comprise thousands of hosts. A Class B network can contain up to 65,000 devices. The number of class B addresses on the internet is around 16,000. Given that class B can be much smaller than class A in relation to the number of hosts. Class B can still be problematic given that not all medium sized organisations has thousands and thousands of hosts.

Class C addresses are used in much smaller networks such as small businesses, small organisations or home networks. The range of a Class C address starts at 192.0.0.0 to 223.0.0.0. The first three octets are used to indicate the network ID the remaining octet is used for the host. A class C address can accommodate up to 254 hosts on a network. Class C can comprise over 2 million networks given it has 24 network bits assigned to the network ID. Given the small size of the available hosts on a class C network and the over abundance of addresses in class B. Many organisations just need more than a few hounds available. The difference between the size of class C compared to class B has led to the practice of subnetting.

Class D addresses are used for multicast addressing, this is a method of sending a package to many devices on the network at the same time. A class D address ranges from 24.0.0.0 to 239.0.0.0.

Class E addresses is a special reserved range of addresses used for experimental purposes. A class E has a range of 240.0.0.0 to 255.0.0.0.