More than 255 computers in the intranet IP planning detailed

The network IP address "main" is divided into three categories of ABC, the following is the scope of coverage:

Class A: 0.0.0.0-127.255.255.255, whose subnet mask is 255.0.0.0 (another way to annotate by subnet mask is/8, which is to convert the subnet mask to binary, from left to 8 1)

Class B: 128.0.0.0-191.255.255.255, whose subnet mask is 255.255.0.0 (another way to annotate by subnet mask is/16, which is to convert the subnet mask to binary, from left to 16 1)

Class C: 192.0.0.0-223.255.255.255, whose subnet mask is 255.255.255.0 (another way to annotate by subnet mask is/24, which is to convert the subnet mask to binary, from left to 24 1)

In order to save space, and to reduce the clerical error, the following subnet masks are labeled with/x, the maximum value of X is 32, and the minimum is 0.

This also involves a subnetting problem:

If ICANN gives you 9.x.x.x, you get to be 9.0.0.0/8 such a Class A network, because the network is too big may be bad management, then you can divide the subnet, divided into 9.1.0.0/16, 9.2.0.0/16, 9.3.0.0/16 、、、 9.255.0.0/16, and then subdivided some are 9.255.1.0/24, 9.255.2.0/24 ... of course, you can split it down a little bit more.

There is also a problem with a subnet merge:

If ICANN awards you 220.220.x.x, you get the standard 220.220.0.0/24, 220.220.1.0/24, 220.220.2.0/24 、、、 220.220.255.0/24 256 Standard Class C networks, And what you need is a large network that can accommodate tens of thousands of nodes, then you can put 220.220.x.x into a network, that is, 222.220.0.0/16, it's called CIDR, we'll use this later.

The part of the plan for the private IP address area is exactly the part of ABC:

10.0.0.0-10.255.255.255 (10.0.0.0/8)

172.16.0.0-172.31.255.255 (172.160.0./16-172.31.0.0/16)

192.168.0.0-192.168.255.255 (192.168.0.0/24-192.168.255.0/24)

There are also some special 127 parts, 169 part, D Class E 224-255 part, and this topic is not

Public network IP address is a very valuable resource today, especially in China.

Then, a considerable number of enterprises, institutions, and even internet cafes, their internal LAN is also really no need to use public network IP, that is, the use of private IP address. According to the scale, a large number of enterprises have chosen the 10.x.x.x, some of the use of 172.16.x.x, a smaller number of internet cafes, used the most popular is 192.168.0.x, a standard Class C network. Note that this is only a habit of use, not a rule.