What is required to route traffic from a public subnet to the internet?

To route traffic from a public subnet to the internet, an Internet Gateway is essential. An Internet Gateway serves as a bridge between your VPC and the internet, enabling internet connectivity for resources that are placed in public subnets. When you attach an Internet Gateway to your VPC, it allows instances within public subnets to have a public IP address, enabling them to send and receive traffic directly from the internet.

For public subnets, routing traffic to the Internet Gateway is typically configured in the subnet's routing table, which routes outbound internet traffic to the Internet Gateway. This ensures that any traffic originating from an instance in the public subnet can reach the internet and can also receive incoming traffic from the internet.

The other options do not serve the same purpose as the Internet Gateway. A NAT Gateway is used for providing internet access to instances in a private subnet and does not facilitate direct access from a public subnet. Routing tables are used to dictate the paths that traffic takes within the network but do not, by themselves, establish a connection to the internet. A VPN Connection is for securely connecting on-premises networks to AWS and is not applicable for routing traffic from a public subnet to the internet.