What Is the Purpose of a Subnet Mask?

A subnet mask is a networking function similar to that of IP addresses. Subnet masks are usually written in 32 bits, and they are used to organize members of a subnet group according to their network settings.

Subnet masks are most useful in determining the subnet of a given IP address. Each IP address is composed of a network and host address, each of which is represented by a different portion of the subnet mask. The host address belongs to the end user’s computer, and the network address refers to the shared connection used by an office, home or other group of computers. This distinction allows the network to identify which subnet an IP address comes from through bitwise and operation methods, promoting additional security and better organization. IP subnet masks are typically set automatically by an IP subnet mask calculator.

Because networks are so complex, the practice of subnetting makes things simple by dividing the network into two or more parts. Because subnet masking divides the user’s information into both host and network address, network administrators can set more stringent controls that are relevant for each user. Learning how to use a subnet mask is necessary when configuring the TCP/IP control on any Microsoft Windows computer.