IPv4 Address Classes

Class A - first bit is 0 (First octet 1-127)

Class B - first TWO bits are 10 (First octet is 128-191)

Class C - first THREE bits are 110 (First octet is 192-223)

Class D - first FOUR are 1110 (First octet 224-239) Used only for multicasting and thus no network/host specified

Class E - The following IPs 240.0.0.0 to 255.255.255.254. Used for experimentation only. No network/host specified