What is a subnet mask used for?

A subnet mask is a critical component in IP networking that specifically serves to delineate the boundaries between the network part and the host part of an IP address. This differentiation allows devices on the same local area network (LAN) to be identified and routed to appropriately, facilitating efficient communication within that network and between external networks.

When a subnet mask is applied, it works by using a binary representation. The parts of the subnet mask that consist of '1's indicate the network bits, while the '0's indicate the host bits. For example, in the common subnet mask of 255.255.255.0, the first three octets are used for the network identification, while the last octet is reserved for hosts on that specific network. This enables a network to effectively subdivide its address space, which in turn helps in organizing and managing multiple devices.

The other options provided do not accurately reflect the purpose of a subnet mask. Enhancing signal strength pertains more to physical layer concerns in networking rather than addressing. Improving security configurations involves different technologies and methods, such as firewalls and encryption, rather than the use of a subnet mask itself. Determining the speed of an internet connection relates to bandwidth and throughput, which are not functions accomplished by a