Subnet mask

Subnet masks restrict network communication.
• 
Example: Computer 1 can talk to Computer 2
• 
Computer 1
IP Address: 192.168.1.2
Subnet Mask: 255.255.255.0
• 
Computer 2
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 anything that has an IP address that begins with 192.168.1.X.