What is the purpose of a subnet mask in networking?

The purpose of a subnet mask is to determine the network and host portions of an IP address. This is crucial in networking as it enables devices within the same network to communicate efficiently. The subnet mask is a 32-bit number that separates the IP address into the network address and the host address. The bits set to '1' in the subnet mask indicate the network portion, while the bits set to '0' indicate the host portion.

For instance, in an IP address of 192.168.1.10 with a subnet mask of 255.255.255.0, the first three octets (192.168.1) represent the network, and the last octet (10) identifies the specific device within that network (host). This division helps routing protocols determine which devices are on the same local network and which ones are on different networks, guiding packets to their appropriate destinations.

In contrast, translating domain names relates to how we access websites via human-friendly URLs instead of numeric IP addresses, which is handled by DNS (Domain Name System). Connecting different networks is a function of routers and gateways, which facilitate communication between distinct networks. Assigning MAC addresses involves network interface cards (NICs) and hardware addressing rather than IP addresses