Subnet Usage Guidelines

Subnet Overview

A subnet is a unique CIDR block with a range of IP addresses in a VPC. All resources in a VPC must be deployed on subnets. Subnets in a VPC cannot overlap with each other.

Figure 1 Subnet

Subnet Planning Suggestions

• How Do I Determine How Many Subnets I Need?
• How Do I Plan CIDR Blocks for VPCs and Subnets?

• Can Subnets Communicate with Each Other?
• Can I Change the CIDR Block of a Subnet?
• How Do I Make the Changed DHCP Lease Time of a Subnet Take Effect Immediately?
• How Can I Make a Domain Name in a Subnet Take Effect Immediately After Being Changed?