WKLD.10 – Deploy private resources into private subnets
Deploy resources that don’t require direct internet access, such as EC2 instances, databases, queues, caching, or other infrastructure, into a VPC private subnet. Private subnets don’t have a route declared in their route table to an attached internet gateway and cannot receive internet traffic. Traffic originating from a private subnet that is destined for the internet must undergo network address translation (NAT) through either a managed AWS NAT Gateway or an EC2 instance running NAT processes in a public subnet. For more information about network isolation, see Infrastructure security in Amazon VPC (Amazon VPC documentation).
Use the following practices when creating private resources and subnets:
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When creating a private subnet, disable auto-assign public IPv4 address.
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When creating private EC2 instances, disable Auto-assign Public IP. This prevents a public IP from being assigned if the instance is unintentionally deployed into a public subnet via misconfiguration.
You specify the subnet for a resource as part of its configuration, when required. You can
deploy a VPC that follows best practices using the Modular and Scalable VPC Architecture Quick Start