ECS instance subnet division and subnet mask representation method

This article introduces the ECS instance subnet division and subnet mask representation method, and focuses on the specific steps. The content of this article is compact, and I hope you can gain something from it.

ECS instance subnet division and mask representation method

Subnet mask representation method

Subnet mask There are generally two representation methods:

Method 1: Represented by dotted decimal notation in the same format as the IP address, such as:

Class B IP address: 255.255.0.0

Class C IP address: 255.255.255.0

Method 2: Add a backslash (/) and a number from 1 to 32 after the IP address, where the numbers from 1 to 32 represent the network identifier in the subnet mask bit length.

For example, if WAF needs to add a whitelist, it can be represented by method two:

For example, the subnet mask 112.124.214.0/24 is equivalent to 255.255. 255.0.

Subnet division

Take the IP address 192.168.1.0/26 and its mask as an example:

IP: 192.168 .1.0/26

Mask: 255.255.255.192

Its binary representation is: 11111111.11111111.11111111.11000000.

The first 24 bits are the network address, and the last 8 bits are the host address.

The first two digits of the host address are set to 1, therefore:

Number of subnets: 2 2 - 2 = 2

block size = 256 - 192 = 64

The subnet IP range is:

The available IP range of the first subnet: 192.168.1.65 - 192.168.1.126

Network address: 192.168.1.64

Broadcast address: 192.168.1.127

Available IP range for the second subnet: 192.168.1.129 - 192.168.1.190

Network address: 192.168.1.128

Broadcast address: 192.168.1.191

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