subnet mask
A subnet mask is a numerical label used in computer networking to divide an IP address into two parts: the network and the host. It helps identify which portion of the IP address refers to the network itself and which part refers to individual devices within that network. Subnet masks are typically written in the same format as IP addresses, using four sets of numbers separated by periods.
By using a subnet mask, network administrators can create smaller, manageable networks within a larger network, improving performance and security. Common subnet masks include 255.255.255.0 for small networks and 255.255.0.0 for larger ones.