Which component is essential for allowing resources in a private subnet to access the internet?

A NAT (Network Address Translation) gateway is essential for enabling resources located within a private subnet to access the internet. In cloud environments, private subnets do not have direct access to the internet for security reasons. A NAT gateway serves as an intermediary that allows instances or resources in the private subnet to initiate outbound traffic to the internet while preventing inbound traffic from the internet to those resources.

When resources in a private subnet need to access external services, such as software updates or web services, they send their requests to the NAT gateway, which then translates the private IP addresses of those resources to a public IP address before forwarding the requests to the internet. This process effectively masks the internal structure of the network while permitting necessary external communication.

While components such as network access control lists, route tables, and security groups play important roles in managing network traffic, they do not specifically provide the necessary functionality for private subnet resources to initiate internet access. Network access control lists control inbound and outbound traffic at the subnet level; route tables determine how traffic is directed within the network; and security groups serve to filter traffic to specific resources based on defined rules, but none of these components alone facilitate the connection to the internet from a private subnet as effectively as a NAT gateway does.