IP address category

The, B, and C3 categories (as shown in the following table) are allocated by internetnic globally, and Class D and Class E are special addresses.

Class a ip Address
A Class a ip address refers,
In the four segments of the IP address, the first segment is the network number, and the remaining three segments are the numbers of the local computer. If the IP address is expressed in binary format, the Class a ip address consists of a 1-byte network address and
A three-byte host address. The maximum value of the network address must be "0 ". In a, the network ID is 7 characters long, the host ID is 24 characters long, and the number of class A network addresses is small.
Hundreds of thousands of large networks.
Class a ip address range: 1.0.0.1-126.255.254 (Binary: 00000001 00000000 00000000 00000001-01111110 11111111 11111111 11111110 ).
The subnet mask of A-type IP addresses is 255.0.0.0. the maximum number of hosts supported by each network is 256 to the power of 3-2 = 16777214.

Class B IP Address
A Class B IP address refers to a network number in the four segments of the IP address ,. If binary representation is used
If the IP address is used, the B-type IP address consists of a 2-byte network address and a 2-byte host address. The maximum IP address must be "10 ". The network ID of a Class B IP address is 14 characters long and the host ID is
The length is 16 bits, and the class B network address is suitable for medium-sized networks. Each network can accommodate more than 60 thousand computers.
Class B IP address range: 128.1.0.1-191.254.255.254 (binary representation: 10000000 00000001 00000000 00000001-10111111 11111110 11111111 11111110 ).
The subnet mask of the B-type IP address is 255.0.0, and the maximum number of hosts supported by each network is 256 to the power of 2 = 65534

Class c ip address
A Class C IP address refers, in the four segments of the IP address, the first three segments are network numbers, and the remaining segments are local
Computer numbers. If the IP address is expressed in binary format, the class c ip address consists of a 3-byte network address and a 1-byte host address. The maximum network address must be 110 ". In Class c ip address
, the network ID is 21 characters in length, the host ID is 8 characters in length, and the number of class C network addresses is large, which is suitable for small-scale local networks, each network can contain up to 254 computers.
Class c ip address range: 192.0.1.1-223.255.254.254 (binary representation: 11000000 00000000 00000001 00000001-11011111 11111111 11111110 11111110 ).
the subnet mask of a Class c ip address is 255.255.255.0. the maximum number of hosts supported by each network is 256-2 = 254

In addition to the preceding three types of IP addresses, there are also several special types of IP addresses, which are specified by the TCP/IP protocol, all the addresses starting with "lll0" in the first byte of the IP address
are called multicast addresses. Therefore, any IP address whose first byte is greater than 223 or less than 240 is a multicast address. Each word in the IP address
corresponds to the address ("0.0.0.0") corresponding to the current host; each byte in the IP address is 1 IP address ("255.255.255.255") is the broadcast address of the current subnet
. All IP addresses that use "llll0" will be reserved for future use; the IP address cannot start with "127". The numbers 127.0.0.1
to 127.1.1.1 in the IP address are used for loop testing. For example, 127.0.0.1 can represent the IP address of the Local Machine and "http: // 127.0.0.1 "to test the Web server configured on the local machine. The first six-digit Group of the network ID cannot be set to "0", and "0" indicates the local network. Class d ip address
A byte starts with "1110" and 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. The address range is 224.0.0.1-239.20.254. Class e ip addresses start with "11110" and are retained for future and lab use.