What is a subnet mask used for?

A subnet mask is a crucial component in IP networking that is used to determine which part of an IP address represents the network and which part represents the host. Each IP address consists of two main sections: the network portion, which identifies a specific network, and the host portion, which identifies a specific device on that network.

The subnet mask works by performing a bitwise AND operation with the IP address. This operation helps isolate the network portion of the address from the host portion, effectively allowing devices to communicate within the same local area network while also identifying how to route traffic to different networks.

Understanding the subnet mask allows network administrators to segment networks appropriately, manage IP address allocations, and optimize network routing. This clarity in distinguishing between the network and host portions is vital for effective communication within IP networks, making the subnet mask an essential tool in networking.