What is the role of an Internet Gateway (IGW) in a VPC?

The role of an Internet Gateway (IGW) in a Virtual Private Cloud (VPC) is primarily to facilitate connections between instances in the VPC and the internet. An IGW serves as a target for route tables for internet-routable traffic and allows inbound and outbound traffic to flow from the VPC to the internet.

When an instance in a public subnet needs to communicate with the internet, the IGW enables that connection by translating private IP addresses to public IP addresses and vice versa. This is crucial for any application that requires public visibility, such as web servers or applications that need to receive traffic from users on the internet.

Due to its nature, an IGW is a scalable, redundant component that provides high availability for the applications running within a VPC, ensuring they can maintain an active connection with external clients and services. This aspect distinguishes the Internet Gateway from other networking components, which may focus on security, load balancing, or private networking functionalities.