IPv4 Address Classes
| Beginning Byte(s) | Class | Usage | Can they be used as a Public, Static IP Address? |
Notes |
# of Possible Networks | Max.# of Hosts per Network |
Approx. Total Addresses |
|---|
| 0 | | local network | No |
|
| |
|
| 1-126 | A | class A network ID's | Yes - with exceptions |
10.0.0.X is sometimes used for private networks |
126 | approx. 16.8 million |
2.1 billion |
| 127 | | loopback or local host | No |
127.0.0.1 refers to the local host |
|
|
|
| 128.0 | | local network | No |
|
|
|
|
| 128.1 - 191.254 | B | Class B network ID's | Yes |
|
approx. 16,000 | 65,534 |
1 billion |
| 191.255 | B | Used for broadcasts | No |
|
|
|
|
| 192.0.0 | | local network | No |
|
|
|
|
| 192.0.1 - 223.255.254 | C | Class C network ID's | Yes -with exceptions |
192.168.X.X is commonly used for private networks |
approx. 2 million | 254 |
.5 billion |
| 223.255.255 | C | Used for broadcasts | No |
|
|
|
|
| 224.0.0.1 - 239.255.255.254 | D | Class D network ID's for multicasting | No |
|
|
|
|
| 240.0.0.1 - 247.255.255.254 | E | Class E network ID's are experimental | No |
|
|
|
|
|
3.7 billion |
There are about 3.7 billion possible public IP addresses
|
