What is the purpose of the subnet mask in an IP configuration?

The purpose of the subnet mask in an IP configuration is to determine the network and host portions of an IP address. The subnet mask works in conjunction with the IP address to define which part of the address corresponds to the network and which part corresponds to the individual device (or host) within that network.

For example, in an IPv4 address such as 192.168.1.10 with a subnet mask of 255.255.255.0, the subnet mask indicates that the first three octets (192.168.1) represent the network part, while the last octet (10) identifies the specific device within that network. This distinction is crucial for routing traffic efficiently within local networks and across the internet.

By understanding how the subnet mask segments the IP address, network devices can accurately route packets and ensure they reach the correct destination. This mechanism also plays a significant role in defining subnets and managing IP address allocation within larger organizations or service providers.