A subnet mask is a 32-bit number used in IP networking to divide an IP address into two parts: the network portion and the host portion. It helps determine which part of an IP address refers to the network and which part refers to the individual devices (hosts) within that network.
The subnet mask consists of a series of consecutive 1s followed by a series of 0s. The 1s indicate the bits that are part of the network address, while the 0s indicate the bits that are available for host addresses. For example, a common subnet mask for a Class C network is 255.255.255.0, which in binary is 11111111.11111111.11111111.00000000. This means that the first 24 bits are used for the network address, and the last 8 bits are used for host addresses.
Subnet masks are essential for routing traffic within and between networks, as they help devices determine whether an IP address is on the same local network or if it needs to be routed to a different network.
