subnet mask

A subnet mask is a 32-bit number used in IP networking to divide an IP address into network and host portions. It determines which part of an IP address refers to the network and which part refers to the host. Subnet masks enable network administrators to create subnetworks, improving network efficiency and security by controlling traffic flow between subnets. Common subnet masks include 255.255.255.0 (for a /24 network) and 255.255.0.0 (for a /16 network). Subnetting helps in efficient IP address allocation, reduces broadcast traffic, and enhances network performance. Understanding subnet masks is crucial for network configuration, troubleshooting, and implementing effective network segmentation strategies.