How Does Subnet Mask Work?

A subnet mask helps computers know which other computers are nearby on the same network, like a neighborhood sign that tells you who lives in your block.

Imagine you're playing with toy blocks. Each block has a number on it, and some numbers are from your group, while others are from different groups. A subnet mask is like a special magnifying glass that lets you see which parts of the block numbers belong to your group, and which ones are from other groups.

Think of an IP address as a full name, like "Sarah Johnson", and the subnet mask as a tool that helps you figure out if someone is in your class or another class.

For example, if your friend has the same first part of their name as yours, they’re probably in your class too.

A subnet mask does something similar with numbers. It hides parts of an IP address so computers can tell who’s on the same network, like knowing whether someone is from your block or another block.

When a computer wants to send a message, it checks if the receiver is on the same block using the subnet mask, just like you’d check names to see if they're in your class.