Guide: Understanding IP Address Classes

What are IP Address Classes?
Internet Protocol (IP) Address Classes divide the IP address space into segments. The five classes, identified by the first four bits, are Class A, B, C, D, and E. Class A, B, and C are the most commonly used for network addressing.
Why are IP Address Classes Important?
IP Address Classes play a critical role in organizing the IP address system, distinguishing network address from host address and supporting large, medium, and small networks.
How Do IP Address Classes Work?
Class A holds a large number of IP addresses with a smaller number of networks. Conversely, Class C represents a small number of IP addresses with a large number of networks, while Class B offers a balance between the two. The fifth and sixth classes, D and E, are used for multicast and experimental purposes, respectively.
Exam Tips: Answering Questions on IP Address Classes
Understand the range of each class and know how to recognize an IP address class by just looking at the initial figures. Pay attention to the differences between the classes; this can be key to knowing how many networks or hosts a particular class can provide. Familiarize yourself with Class D and E as they often appear in exams.