The scope of use of Class A IP addresses, the ABC class division of IP addresses

The single-cast IP address from to . (which is a fixed special IP for loopback testing) to a private address.

A Class A network can provide 16777214 host addresses, that is, 2 24-2 [the reason for minus 2 here is that all 0 host addresses represent a single network address to which "this host" is connected, and all 1s represent "all", that is, all hosts on the network].

There are 2 32 IP address spaces and 2 31 Class A addresses as a whole, accounting for 50 per cent of the entire IP address space.

The default subnet mask for Class A addresses is.

The Class A IP address ranges are as follows.

It should be emphasized here that the numbers 0 and 127 are not used as the IP address of the host, the number 127 is reserved for the internal loopback function, and the number 0 indicates that the address is a local host and cannot be transmitted, but 0 and 127 do belong to class A addresses, so there are only 126 addresses at most for class A addresses. Private addresses and reserved addresses in Class A addresses: to private addresses (the so-called private addresses are addresses that are not used on the Internet, but are used in local area networks).

To is reserved for the address, which is used for cyclic testing. To is also a reserved address, which is used to represent all IP addresses. The default subnet mask for Class A addresses is.

To put it simply:

A Class A IP address consists of a 1-byte (8-bit each) network address and a 3-byte host address, with the highest bit of the network address having to be "0", i.e. the first numeric range is 1,126. Each Class A address can connect to 16387064 hosts, and the Internet has 126 Class A addresses.

2 Class B IP addresses.

A Class B IP address consists of a 2-byte network address and a 2-byte host address, and the highest digit of the network address must be "10", i.e. the first numerical range is 128 191. Each Class B address can connect to 64,516 hosts, and the Internet has 16,256 Class B addresses.

3 Class C IP addresses.

A Class C address consists of a 3-byte network address and a 1-byte host address, and the highest bit of the network address must be "110", i.e. the first numerical range is 192 223. Each Class C address can connect to 254 hosts, and the Internet has 2054512 Class C addresses.

In general, it is like this as follows.

The IP addresses of the network are "mainly" divided into three categories: A, B, C, and the following:

Coverage: Class A: - Whose subnet mask is marked by another annotation method of subnet mask is 8, which is to convert the subnet mask to binary, counting from the left 8 1).

Category B: - Whose subnet mask is another way to annotate by subnet mask is 16, which is to convert the subnet mask to binary, counting from the left 16 1).

Category C: - Whose subnet mask is marked by another annotation method of subnet mask is 24, which is to convert the subnet mask to binary, counting from the left 24 1).

Class A addresses are used for a small number (up to 27-2) networks with more than 216 hosts, and each Class A network can accommodate up to 224-2 hosts.

Class B addresses are used for medium-sized networks with a number of no more than 28 216 hosts, and a maximum of 214-2 Class B networks.

Class C addresses are used for a large number of small networks where each network can only accommodate 28-2 hosts, and Class C networks are up to 221-2

In IPv4, a Class A IP address, in which the first segment of the IP address is the network number and the remaining three segments are the host number. And the highest bit of the network address must be "0". Class A addresses range from:

A Class B IP address in IPv4, in which the first two segments of the four-segment IP address are network numbers. If you use binary to represent a Class B IP address, the Class B IP address consists of a 2-byte network address and a 2-byte host address, and the highest bit of the network address must be "10". Range of Class B IP addresses:

In IPv4, the C IP address, in which the mu is sold in the four segments of the IP address, the first three segments of the four segments of the number are the network number, and the remaining segment of the number is the host number. A Class C IP address consists of a 3-byte network address and a 1-byte host address, and the highest digit of the network address must be "110". Range of Class C IP addresses:

Class A IP address address range.

From to , the class B IP address template enclosure is from , and the class C IP address range is from.

Class A: e69da5e887aa62616964757a686964616f31333431376562 (default subnet mask: or 0xff000000) The first byte is the network number, and the last three bytes are the host number.

This type of IP address is preceded by "0", so the network number of the address can be between 1 126. It is generally used for large networks.

Class B: (Default Subnet Mask: or 0xffff0000) The first two bytes are the network number and the last two bytes are the host number.

This type of IP address is preceded by "10", so the value of the IP address is between 128 and 191. It is generally used for medium-sized networks.

Class C: (Subnet Mask: or 0xffffff00) The first three bytes are the network number and the last byte is the host number.

This type of IP address is preceded by "110", so the value of the IP address is between 192 and 223. It is generally used in small networks.

It should be good or bad.

There is usually a specific way to define this.

You know the right answer, what else to ask, it's boring.