Episode 55: Classful vs. Classless Addressing — Understanding IP History
Before CIDR and modern subnetting, networks relied on a rigid system of classful addressing. In this episode, we take a historical look at how IP addressing originally worked using Class A, B, and C address ranges. You’ll learn why classful addressing was inefficient and how it limited IP allocation, leading to wasted address space and early depletion of IPv4 blocks. Understanding this context helps clarify why subnetting and CIDR were introduced to begin with.
We then explain how classless addressing (CIDR) allows for more flexible and granular subnetting by ignoring fixed boundaries and focusing on prefix lengths. You’ll also learn how this shift led to more efficient routing and allowed the internet to scale as demand exploded. While classful addressing is rarely used today, it still appears on the exam—and grasping its role makes modern subnetting concepts easier to understand.
