Subnetting

Each IP address consists of a subnet mask. All the class types, such as Class A, Class B and Class C include the subnet mask known as the default subnet mask. The subnet mask is intended for determining the type and number of IP addresses required for a given local network. The firewall or router is called the default gateway. The default subnet mask is as follows:

• Class A: 255.0.0.0
• Class B: 255.255.0.0
• Class C: 255.255.255.0
  

The subnetting process allows the administrator to divide a single Class A, Class B, or Class C network number into smaller portions. The subnets can be subnetted again into sub-subnets.

Dividing the network into a number of subnets provides the following benefits:

• Reduces the network traffic by reducing the volume of broadcasts
• Helps to surpass the constraints in a local area network (LAN), for example, the maximum number of permitted hosts.
• Enables users to access a work network from their homes; there is no need to open the complete network.