aws - VPC networking components

internet gateway:

An internet gateway is a horizontally scaled, redundant, and highly available VPC component that allows communication between your VPC and the internet.

An internet gateway serves two purposes: to provide a target in your VPC route tables for internet-routable traffic, and to perform network address translation (NAT) for instances that have been assigned public IPv4 addresses.

Public and private subnets

If a subnet is associated with a route table that has a route to an internet gateway, it‘s known as a public subnet. If a subnet is associated with a route table that does not have a route to an internet gateway, it‘s known as a private subnet.