Subnet mask

Subnet masks restrict network communication.
Example: Computer1 can talk to Computer2
Computer1
IP Address: 192.168.1.2
Subnet Mask: 255.255.255.0
Computer2
IP Address: 192.168.1.3
Subnet Mask: 255.255.255.0
Note Note
0 denotes that there is no limit to communication at this part of the address.
In the above example, we can communicate with any device that has an IP address that begins with 192.168.1.X.