| Klasse | Führendes Byte dezimal | Beispiel | Führendes Byte Binär | Privater Bereich |
| A | 1-126 | 52.0.0.0 255.0.0.0 |
0nnn nnnn | 10.0.0.0-10.255.255.255 |
| B | 128-191 | 179.166.0.0 255.255.0.0 |
10nn nnnn | 172.16.0.0-172.31.255.255 |
| C | 192-223 | 220.79.144.0 255.255.255.0 |
110n nnnn | 192.168.0.0-192.168.255.255 |