Subnet mask (subnet mask) is also called network mask, address mask, and subnet mask. It is a 32-bit address used to shield part of the IP address to distinguish the network identifier and the host identifier, and explain Is the IP address on the local area network or on the remote network?
#What is the default subnet mask for class a addresses?
The default subnet mask of Class A is:255.0.0.0
Extended information:
Subnet masks are divided into two categories:
1. Default (automatically generated) subnet mask: The default subnet mask means that no subnets are divided, and the corresponding network number bits are all Set to 1 and host numbers are set to 0.
(1), Class A network default subnet mask: 255.0.0.0
(2), Class B network default subnet mask: 255.255.0.0
(3), Class C network default subnet mask: 255.255.255.0
2. Custom subnet mask: It divides a network into several subnets, and each segment needs to use a different subnet mask. Network number or subnet number, in fact we can think of it as dividing the host number into two parts: subnet number and subnet host number. The format is as follows:
(1), IP address without subnetting: network number, host number
(2), IP address after subnetting: network number, subnet number Subnet host number
That is to say, after the IP address is divided into subnets, part of the previous host number position is given to the subnet number, and the rest is the subnet host number.
The subnet mask is a 32-bit binary number, and its subnet host identification part is all "0". You can use the subnet mask to determine whether two hosts are on the same subnet. If the IP addresses of two hosts are ANDed with their subnet masks and the result is the same, it means that the two hosts are in the same subnet.
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