Internet Gateway (IGW)
- What it is
- A horizontally-scaled, redundant Amazon VPC component that allows two-way traffic between the VPC and the internet.
- One IGW per VPC.
- What makes a subnet public
- A subnet is public when its route table sends
0.0.0.0/0to the IGW and the resource has a public IP or Elastic IP.
- A subnet is public when its route table sends
- Does
- Provides a target in route tables for internet-routable traffic.
- Performs network address translation for instances with public IPv4 addresses.
- Not to be confused with
- NAT Gateway — outbound-only for private subnets. An IGW is two-way for public subnets.
- AWS VPN / AWS Direct Connect — connect the VPC to your own network, not the public internet.