Public IP Addresses
Class |
1st Octet Decimal Range |
1st Octet High Order Bits |
Network/Host ID (N=Network, H=Host) |
Default Subnet Mask |
Number of Networks |
Hosts per Network (Usable Addresses) |
A |
1 – 126* |
0 |
N.H.H.H |
255.0.0.0 |
126 (27 – 2) |
16,777,214 (224 – 2) |
B |
128 – 191 |
10 |
N.N.H.H |
255.255.0.0 |
16,382 (214 – 2) |
65,534 (216 – 2) |
C |
192 – 223 |
110 |
N.N.N.H |
255.255.255.0 |
2,097,150 (221 – 2) |
254 (28 – 2) |
D |
224 – 239 |
1110 |
Reserved for Multicasting |
E |
240 – 254 |
1111 |
Experimental; used for research |
Note: Class A addresses 127.0.0.0 to 127.255.255.255 cannot be used and is reserved for loopback and diagnostic functions.
Private IP Addresses
Class |
Private Networks |
Subnet Mask |
Address Range |
A |
10.0.0.0 |
255.0.0.0 |
10.0.0.0 – 10.255.255.255 |
B |
172.16.0.0 – 172.31.0.0 |
255.240.0.0 |
172.16.0.0 – 172.31.255.255 |
C |
192.168.0.0 |
255.255.0.0 |
192.168.0.0 – 192.168.255.255 |