IPv4 Address Classes (now obsolete)

Class	First Bits	IP Address Range	Description
A	0	0.X.X.X - 127.X.X.X 00000000.X.X.X - 01111111.X.X.X	8-bits for network-prefix 24 bits for host-suffix
B	10	128.X.X.X - 191.X.X.X 10000000.X.X.X - 10111111.X.X.X	16-bits for network-prefix 16 bits for host-suffix
C	110	192.X.X.X - 233.X.X.X 11000000.X.X.X - 11011111.X.X.X	24-bits for network-prefix 8 bits for host-suffix
D	1110	224.X.X.X - 239.X.X.X 11100000.X.X.X - 11101111.X.X.X	for multicast purposes
E	1111	240.X.X.X - 255.X.X.X 11110000.X.X.X - 11111111.X.X.X	for experimental purposes

Source/Loopback/Localhost Address

Address Type & Network-Host Separation

Address Range

Total Number of Addresses

127.X.X.X

01111111.X.X.X

16,777,216 IP addresses

Address Type & Network-Host Separation

Address Range

Total Number of Addresses

10.X.X.X

00001010.X.X.X

16,777,216 IP addresses

172.16.X.X - 172.31.X.X

10101100.00010000.X.X - 10101100.00011111.X.X

1,048,576 IP addresses

Class C in terms of first 3 bits

Class B in terms of network and host separation

192.168.X.X

11000000.10101000.X.X

65,536 IP addresses

Group Address Types	Address Range	Description
Local Scope Addresses	224.0.0.X 11100000.0.0.X	addresses are used on a local link Time-To-Live (TTL) of 1 224.0.0.1 - all hosts 224.0.0.2 - all multicast routers 224.0.0.5 - all OSPF 224.0.0.6 - all OSPF DR (Designated Router)
GLOP	233.X.X.0 - 233.X.X.255 11101001.X.X.0 - 11101001.X.X.255	Autonomous System (AS)'s ID number ASN is inserted in middle octets "X.X"
Transient Addresses - Global Range	224.0.1.0 - 238.255.255.255	224.2.X.X in the multicast backbone (Mbone)
Transient Addresses - Site-Local Scope	239.253.0.0/16
Transient Addresses - Organization Local Scope	239.192.0.0/14