What is the subnet mask length? What do you think?

Subnet mask. is a 32-bit address that is associated with an IP address.

A combination of techniques. It has two main functions, one is used to mask part of the IP address to distinguish between network identity and host identity, and to indicate whether the IP address is on a local area network or a remote network. Second, it is used to divide a large IP network into several small sub-networks.

Subnets are used to reduce IP waste. Because with the development of the Internet, more and more networks are generated, some networks are more than hundreds, and some are only a few, so a lot of IP addresses are wasted, so it is necessary to divide subnets. Using subnets can improve the efficiency of your network applications.

Calculated using the number of hosts

1. Convert the number of hosts to binary.

to represent. 2. If the number of hosts is less than or equal to 254 (note that the two reserved IP addresses are removed), then the number of binary bits of the host is n, here it must be n<8. If it is greater than 254, then n>8, which means that the host address will occupy more than 8 bits.

3. It is used to set all the bits of the host address of this type of IP address to 1, and then set all the n bits to 0 from back to front, which is the subnet mask value.

2. The binary is a ten-digit number, n = 10

3. Set all the host addresses of the subnet mask of the Class B address to 1 to obtain.

Then from back to front, place the last 10 position 0, that is:

Namely. This is the subnet mask that is intended to be divided into Class B IP addresses with 700 hosts.

The length of the subnet mask is 32 bits, and the left one is the network bit, which is represented by the binary number "1", and the number of 1 is equal to the length of the network bits; The one on the right is the host bit, which is represented by the binary number "0", and the number of 0 is equal to the length of the host bit.

If the custom subnet mask divides a network into several subnets, and you need to use a different network number or subnet number for each segment, you can actually think of it as dividing the host number into two parts: the subnet number and the subnet host number. For example:

Only through the subnet mask can you explain the relationship between the subnet in which a host is located and other subnets. In this way, in order to allow the mask and IP address to do bitwise calculations, 0 is used to cover the number of original hosts, and the number of the original network segment is not changed, and it is easy to determine the number of hosts in the subnet by the number of bits of 0.

Part of the previous host number location was given to the subnet number, and the rest was the subnet host number. The subnet mask is a 32-bit binary number, and its subnet host ID is identified with a full "0". You can use the subnet mask to determine whether two hosts are in the same subnet.

If the IP addresses of the two hosts are the same as those of their subnet masks, the two hosts are in the same subnet.

A subnet mask is a 32-bit address that is a technique used in conjunction with an IP address. The length of the subnet mask is also 32 bits, and it can also be in decimal form. For example, a subnet mask in binary form:

1111 0000 in decimal form:

Subnet mask, also known as network mask, address mask, and subnet mask, is a bit mask used to indicate which bits of an IP address identify the subnet where the host is located, and which bits identify the host. The subnet mask cannot exist on its own, it must be used in conjunction with an 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.

A subnet mask is a 32-bit address that is used to mask a portion of an IP address to distinguish between network and host identities and to indicate whether the IP address is on a local area network or a remote network.

The length of the subnet mask is also 32 bits.

On the left is the network bits, represented by the binary number "1", the number of 1 is equal to the length of the network bits; On the right is the host bit, which is represented by the binary number "0", and the number of 0s is equal to the length of the host bit. Like binary IP addresses, the subnet mask consists of 1 and 0, and the 1s and 0s are sequential, respectively.

However, the subnet mask is different from the IP address: the 32-bit binary number of the IP address can be arbitrarily 0 or 1, that is, the IPv4 address theoretically has 2 to the 32nd power - 2 (remove the network itself with all zeros or the broadcast address with all 1s).

The binary composition of the subnet mask is only two parts, representing the 1 of the network bit and 0 representing the host bit, and the 1 on the left and 0 on the right are consecutive respectively, so the decimal representation of the base 2 cannot be arbitrarily valued, and the theoretical IPv4 subnet mask is only 30. The subnet mask is used to determine whether the IP addresses of any two computers belong to the same subnet.

The network address and host number of a device are determined through the binary of the IP address and the binary of the subnet mask, that is, the network part and the host part of a network are distinguished by the subnet mask. Once the subnet mask is set, the network address and host address are fixed. One of the most striking features of a subnet is that it has a subnet mask.

Like the IP address, the length of the subnet mask is also 32 bits and can also be in decimal form. For example, a subnet mask in binary form: 1111 0000 in decimal form: .

24 28 30-bit subnet mask.

The difference is as follows: 24 bits means 24 binaries.

The 1 is like this: , converted to decimal.

The representation is:

28 bits: , converted to decimal system.

30 digits: , converted to decimal system.

The setting of the subnet mask must follow certain rules. with binary IP address.

Similarly, the subnet mask consists of 1 and 0, and 1 and 0 are sequential. The length of the subnet mask is also 32 bits, and on the left is the network bit, which is represented by the binary number "1", and the number of 1 is equal to the length of the network bit; On the right is the host bit, which is represented by the binary number "0", and the number of 0s is equal to the length of the host bit.

By default, the subnet mask is set to:

For Class A addresses, the default subnet mask is;

For Class B addresses, the default subnet mask is;

For Class C addresses, the default subnet mask is.

To set the subnet mask:

1. Open the currently connected network and click the "Properties" page.

2. In the network properties page, double-click to open the Internet Protocol version 4 option.

3. In the settings page that opens, select the setting to "Use the following IP address" to enter the subnet mask.