Network Address classification

0.0.0.0 any of the native IP addresses.
127.0.0.1 Local loopback Address

Class A
The 1th byte is the network address, and the other 3 bytes are the host address. The highest bit of the 1th byte is fixed to 0
0000 0000 ~ 0111 1111
1.0.0.1–126.255.255.255

Class B
The 1th and 2nd bytes are network addresses, and the other 2 bytes are host addresses. The first two bits of the 1th byte are fixed to 10
10 00 0000 0000 0000 ~ 10 11 1111 1111 1111
128.0.0.1–191.255.255.255

Class C
The first 3 bytes are the network address, and the last 1 bytes are the host address. The first 3 bits of the 1th byte are fixed to 110
1100 0000 0000 0000 0000 0000 ~ 1101 1111 1111 1111 1111 1111
192.0.0.1–223.255.255.255

Class D (multicast address)
Without network address and host address, the first 4 bits of the 1th byte are fixed to 1110
224.0.0.1–239.255.255.255
Multicast address: 225.0.0.1--239.255.255.255

Class E (reserved address)
240.0.0.1-255.255.255.255

Network Address classification