When architecting networks in AWS, two common gateways used are internet gateways (IGWs) and NAT gateways (NGWs). At first glance, they may seem interchangeable – both connect resources in your VPC to the internet. However, internet gateways and NAT gateways serve very distinct purposes.

An Internet Gateway (IGW) is a highly available AWS-managed component that enables instances in a public subnet to communicate with the internet. Each type of gateway serves a distinct purpose in managing network traffic, particularly for IPv4 and IPv6 connectivity within Amazon Virtual Private Cloud (VPCs).

You can add a network address translation (NAT) gateway to your AWS Network Firewall architecture, for the areas of your VPC where you need NAT capabilities. AWS provides NAT gateways decoupled from your other cloud services, so you can use it in your architecture only where you need it. This can help you reduce load and load costs.

AWS offers different types of gateways to facilitate internet access and network management. To choose the right gateway, consider your network requirements: Use Internet Gateway (IGW) for publicly accessible instances. Use NAT Gateway for outbound-only internet access in private subnets.