What is the function of a subnet mask?

A subnet mask plays a critical role in determining which part of an IP address is used for the network and which part is used for the host. It does this by using a binary representation where it applies a series of "1s" to denote the network portion and "0s" to indicate the host portion. This enables devices within the same network to communicate effectively without needing to pass through a router, as they can recognize whether an IP address belongs to the local subnet or if it needs to be routed to another network.

For example, 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) indicate the network portion, while the last octet (.10) identifies the specific device (host) within that network. This separation is vital for network organization, efficient communication, and routing.

The other options do not describe the function of a subnet mask. Encrypting IP packets, managing DNS requests, or dynamically assigning IP addresses are tasks associated with different networking concepts and protocols such as security measures, domain name services, and DHCP (Dynamic Host Configuration Protocol), respectively. None of these functions relate to the fundamental purpose of