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IPv4 Address Classes

In the early days of the Internet, the IANA (Internet Assigned Numbers Authority) defined five classes of public IP addresses as shown below.

Ipv4 Address Classes
Class Theoretical Address Range Binary Start Used for
A 0.0.0.0 to 127.255.255.255 0 Very large networks
B 128.0.0.0 to 191.255.255.255 10 Medium networks
C 192.0.0.0 to 223.255.255.255 110 Small networks
D 224.0.0.0 to 239.255.255.255 1110 Multicast
E 240.0.0.0 to 247.255.255.255 1111 Experimental


In practice some of these addresses are reserved for private addresses.


Use the links below to find out more about the three main address classes.

Class A

Class B

Class C

Next: Private IP Addresses