Introduction: The Rigid Old Days
In the early 1980s, the internet was a small, academic project. To keep things organized, engineers created a system called Classful Addressing. They divided all available IP addresses into huge buckets called Classes. While we don’t use this rigid system on the public internet anymore, its terminology still dominates how network engineers talk today.
In this guide, we’ll look at the differences between Class A, B, and C and why they were eventually replaced.
The Three Main Classes
- Class A (Gigantic): Designed for organizations with millions of devices. A single Class A block gave you 16.7 million addresses. (Starts with 0-127).
- Class B (Medium): For large companies and universities. Gave you 65,536 addresses. (Starts with 128-191).
- Class C (Small): For small businesses and homes. Gave you 256 addresses. (Starts with 192-223).
The Problem: Massive Waste
The system was too rigid. If a company needed 300 addresses, a Class C wasn't enough, but a Class B (65,000) was far too large, leading to 64,700 wasted addresses. This waste is why we eventually moved to the more precise **CIDR** system in the 90s.
Conclusion
Understanding IP classes is like learning the history of the world. It shows us how we got here and why the modern 'classless' internet is so much more efficient. Check your address here.