Public and Private Subnets
Subnets are an essential tool for network administrators to manage large networks. Subnetting is achieved by dividing a network into smaller network segments, each with its unique network address and subnet mask. The subnet mask defines the network and host portions of the IP address, allowing the network to determine which devices are on the same network and which require routing.
Dividing a more extensive network into smaller subnets can also enhance network security. Subnets can help improve network security by isolating different parts of the network and allowing better control over access to network resources. This can help prevent unauthorized access to sensitive data or systems.
Figure 10.23: Subnets dividing a larger /16 CIDR range
A public subnet should be used for resources that the internet will access. A private subnet should be used for resources that will not be accessible from the public internet.
