Network Class
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The Five IPv4 Classes
there are five classes: A, B, C, D and E in the IPv4 IP address space. Primarily, class A, B, and C are used by the majority of devices on the Internet. Class D and class E are for special uses. Each class has a specific range of IP addresses.[1]
Within each network class, there are designated IP address that is reserved specifically for private/internal use only. This IP address cannot be used on Internet-facing devices as that are non-routable.
| Class | Public IP Range | Private IP Range | Special IP Range | Subnet Mask | Number of Networks | Number of Hosts per Network |
|---|---|---|---|---|---|---|
| A | 1.0.0.0 to 127.0.0.0 | 10.0.0.0 to 10.255.255.255 | 255.0.0.0 | 126 | 16,777,214 | |
| B | 128.0.0.0 to 191.255.0.0 | 172.16.0.0 to 172.31.255.255 | Automatic Private IP Addressing (APIPA) is a feature with Microsoft Windows-based computers to automatically assign itself an IP address within this range if a Dynamic Host Configuration Protocol (DHCP) server is not available on the network. | 255.255.0.0 | 16,382 | 65,534 |
| C | 192.0.0.0 to 223.255.255.0 | 192.168.0.0 to 192.168.255.255 | 127.0.0.1 to 127.255.255.255
**network testing addresses (also referred to as loop-back addresses). |
255.255.255.0 | 2,097,150 | 254 |
| D | 224.0.0.0 to 239.255.255.255 | Multicasting | ||||
| E | 240.0.0.0 to 255.255.255.255 | Research/Reserved/Experimental |