Categories of Public IP addresses, private IP addresses, and IP addresses

Public and private IP addresses:

A: A Class a ip address consists of a 1-byte network address and a 3-byte host address. The maximum network address must be "0 ",The address range is from 1.0.0.0 to 126.255.255.255. There are 126 available class A networks, each of which can accommodate more than 0.1 billion hosts.

B: A Class B IP address is composed of two bytes of network address and two bytes of host address. The highest bit of network address must be "10 ",The address range is 128.0.0.0 to 191.20.255. There are 16382 available class B networks, each of which can accommodate more than 60 thousand hosts.

C: A Class c ip address consists of a 3-byte network address and a 1-byte host address. The maximum network address must be 110 ".The range is from 192.0.0.0 to 223.20.255. A Class C network can contain more than 2.09 million hosts, and each network can accommodate 254 hosts.

D: the first byte of A Class d ip address starts with "lll0". It is a reserved address. It does not point to a specific network,Currently, this type of address is used in multi-point broadcast (Multicast. A multicast address is used to address a group of computers at a time. It identifies a group of computers that share the same protocol.

E: starting with "llll0", reserved for future use

 

The full zero ("0.0.0.0") Address corresponds to the current host. The IP address ("255.255.255.255.255") of "1" is the broadcast address of the current subnet.

With the development of private IP networks, in order to save the allocable registered IP addresses, a group of IP addresses are used exclusively for private IP networks, called private IP addresses. Private IP address range:

A: 10.0.0.0 ~ 10.20.255.255/8(10.000000000000000000000000 --- 10.111111111111111111111111)

B: 172.16.0.0 ~ 172.31.255.255/12(172.000100000000000000000000 --- 172.000111111111111111111111)

C: 192.168.0.0 ~ 192.168.255.255/16(192.168.20.000000000000 --- 192.168.11111111111111)

These addresses are not allocated by the Internet, and they are not routed on the Internet. Although they cannot be directly connected to the internet, they can still communicate with the Internet through technical means. We can select an appropriate address class as needed and use these addresses as public IP addresses in the internal LAN.