Subnet mask calculator

Subnet mask calculatorIt is very convenient to calculate the subnet mask. It contains five classic subnet mask calculation tools. You can choose freely. It is a must for network management! The subnet mask calculator can also automatically divide class A, B, and C IPs. , you can output the divided subnet mask, subnet bits, maximum number of subnets, host bits, maximum number of hosts, and all subnet lists, and save the results to a text file. Huajun Software Park provides you with subnet mask calculator download.

Basic introduction to subnet mask

Subnet mask (subnet mask) is also called network mask, address mask, and subnet mask. It is a method used to indicate which bits of an IP address identify the subnet where the host is located and which bits identify the subnet where the host is located. Bitmask for the host.

The subnet mask cannot exist alone, it must be used in conjunction with the IP address. The subnet mask has only one function, which is to divide an IP address into two parts: the network address and the host address.

What is the function of subnet mask?

IP addresses use network numbers and host numbers to identify hosts on the network. Only computers under the same network number can "directly" communicate with each other. Computers with different network numbers can communicate with each other through a gateway. However, this division appears to be very inflexible in some cases. For this reason, the IP network also allows it to be divided into smaller networks, called subnets (Subnets), which produces subnet masks. The function of the subnet mask is to determine whether any two IP addresses belong to the same subnet. At this time, only computers on the same subnet can "directly" communicate with each other.

Subnet Mask Calculator Software Features

​​​1. Simplified subnet calculation function

Accurate subnet calculation function: The subnet mask calculator can automatically divide the main IP subnets and output the divided subnet mask, number of subnets, maximum number of subnets, number of hosts, maximum number of hosts, and all list of subnets.

​​​2. Backcalculate the IP addresses divided into subnets

The IP address of the device is divided into the IP address of the sub -network. A IP address & mask that has been divided into a sub -network can be counted as the number of hosts and divided subnets that have been borrowed. The result is displayed on the left side.

​3. Typeset and save the results

Click the Save Result button to save the divided subnet information as a text file in a certain format.

​​​4. Mask conversion function

Input any format (mask digits, mask binary representation, mask decimal representation) to convert the other two formats, which is a good helper for VLSM!

​​​5. Conversion between decimal and binary

                                              Enter decimal or binary numbers to convert between decimal and binary numbers to convert to another representation, which is a powerful tool for manual subnet division!

Subnet mask calculator installation steps

​​ 1. After downloading the subnet mask calculator installation package from this site, unzip it to get the exe installation file

​ 2. Double-click SubNetMaskCalc.exe to use it

How to use the subnet mask calculator

​​​How to use the subnet mask calculator?

​ ​ 1. First, I need to plan my own network. First, enter our IP address range in the calculator. We will find that the available addresses are 1-192.

2. We change the number of digits in the subnet mask calculator to 32 bits. The mask becomes 255.255.255.248, and the available addresses below become 0.1-1.248. There are about 250 masks available. , thus meeting the needs of users.

​​​How to use the subnet mask calculator to convert from binary to decimal?

​ ​ 1. Open the subnet mask calculator and click Binary to Decimal Converter

​​ 2. Enter the code to convert

How to determine the subnet mask?

IP addresses are divided into network numbers and host numbers. To divide a network into multiple subnets, the network number will occupy the original host bits. For example, for a Class C address, which uses 21 bits to identify the network number, it must be divided into Two subnets need to occupy 1 bit of the original host identification bit. At this time, the network number changes to 22 digits and the host identification changes to 7 digits. In the same way, a Class C network can be divided into 4 subnets by borrowing 2 host bits... So how does the computer know whether the network is divided into subnets? This can be seen from the subnet mask. The subnet mask has the same 32 bits as the IP address. The way to determine the subnet mask is that all the bits corresponding to the network number in the IP address are "1", and the bits corresponding to the host number are all "0". If a Class C IP address divided into 2 subnets uses 22 bits to identify the network number, its subnet mask is: 11111111111111111111111110000000, which is 255.255.255.128. So we can know that the default subnet mask of class A address is 255.0.0.0, class B is 255.255.0.0, and class C is 255.255.255.0. The following table shows the subnetting of Class C addresses and related subnet masks:

Number of subnet bits, number of subnet masks, number of hosts, number of available hosts

255.255.255.128128126

255.255.255.1926462

255.255.255.2243230

255.255.255.2401614

255.255.255.24886

255.255.255.25242

This is a method of dividing and distinguishing networks and hosts. It is usually set automatically, but variable length masks (VLSM) can also be used, which means that a network can be configured with different masks. The purpose of this is to make it easier to divide a network into multiple subnets.

How to calculate subnet mask?

​Generally speaking, our subnet mask defaults to 255.255.255.XXX (most Class C addresses are in China, so they usually start with 255.255.255)

Among them, those bits that are all 1 from the left are grouped into a group, representing the subnet number; the remaining bits that are 0 are grouped into a group, representing the host number. For example, for 11100000, 111 represents the subnet number, and 00000 represents Host number. The subnet number is a symbol of the number of subnets. The host number is the number of hosts that can be used by each subnet number. For example, for 11100000, we can divide 8 subnets (000,001,010...111), Each subnet can be used by 32 hosts (00000, 00001, 00010...11111), but please note that usually the host numbers with all 0s and all 1s cannot be used (I don't know why, It is said that it has other special purposes), and a host number is used as a gateway. Therefore, the number of hosts provided by a subnet is generally equal to 2^n-3, n is the maximum host number, that is, the binary number is all 1 pairs. decimal number.

But for this question, there is no need to pay attention to so many things. To divide 4 subnets (i.e. 00, 01, 10, 11), it means that the binary number of XXX is 11000000. (110000) 2 = (192) 10

Therefore, for Class C addresses divided into 4 subnets, the corresponding subnet mask is 255.255.255.192

Replenish:

"It cannot be all 0s or all 1s" is for the host number, which does not include the network number.

You need to divide 4 subnets, that is to say, the numbers of the 4 subnets are 00, 01, 10, 11. This can deduce the first two digits of XXX binary, 11 (that is, the binary number of XXX should be 11000000). For 11000000, we are It is logically divided into a subnet number and a host number, but in fact the computer can only recognize the value of this series of numbers (i.e. 192 in decimal).

Use the subnet mask calculator to easily calculate the result, set the IP address and the number of subnets to be divided, and click Calculate to get the result

Subnet Mask Calculator FAQ

​​​What are the common subnet masks?

The default subnet mask on our computer is 255.255.255.0

         Then there is also a network of 255.255.0.0. The last two numbers can be changed arbitrarily in the range of 0~255, which can provide 2552 IP addresses. But the actual number of available IP addresses is 2552-2, which is 65023.

Subnet mask calculator update log:

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