IP address classes and private IP addresses

IP address classes

Class First octet decimal range
Class A 1 to 126
Class B 128 to 191
Class C 192 to 223

Private IP addresses

Class Address Range
A 10.0.0.0 to 10.255.255.255
B 172.16.0.0 to 172.31.255.255
C 192.168.0.0 to 192.168.255.255