There are two main IPv4 address spaces—the public address space and the private address space
Diff: Public address space is routable via the internet
The public address space is divided into five classes: Class A 0.0.0.0 – 126.255.255.255 Class B 128.0.0.0 – 191.255.255.255 Class C 192.0.0.0 – 223.255.255.255 Class D 224.0.0.0 – 239.255.255.255 Class E 240.0.0.0 – 255.255.255.255
Class D addresses are used for multicast traffic. These addresses are not assignable. Class E addresses are reserved for experimental usage and are not assignable.
classes A, B, and C are commonly used on devices that are directly connected to the internet, such as layer 3 switches, routers, firewalls, servers, and any other network-related device.
The private address space is divided into three classes: Class A—10.0.0.0/8 network block 10.0.0.0 - 010.255.255.255 Class B—172.16.0.0/12 network block 172.16.0.0 - 172.31.255.255 Class C—192.168.0.0/16 network block 192.168.0.0 - 192.168.255.255
title: "IANA IPv4 Special-Purpose Address Registry"
image: "https://www.iana.org/_img/icons/text-xml.png"
description: "Registry Included Below"
url: "https://www.iana.org/assignments/iana-ipv4-special-registry/iana-ipv4-special-registry.xhtml"