Overview
A subnet mask is used to determine which part of an IP address refers to the network and which part refers to the specific host on that network. It is essential for routing and identifying if a destination is local or remote.
How it Works
In binary, a '1' in the subnet mask indicates the network portion, and a '0' indicates the host portion. For example, a mask of 255.255.255.0 (or /24 in CIDR notation) means the first 24 bits are the network ID.
Common Masks
- 255.0.0.0 (/8): Large networks.
- 255.255.0.0 (/16): Medium networks.
- 255.255.255.0 (/24): Small networks (common in homes).