A Route Table defines how network traffic is directed within a VPC. To enable Internet access for EC2 instances in a public subnet, the Route Table associated with that subnet must be updated.
Key Concepts
- Each subnet is associated with exactly one Route Table (either explicitly or via the main Route Table).
- A public subnet must have a route that directs all Internet-bound traffic (
0.0.0.0/0) to the Internet Gateway (IGW).
- The Route Table must be associated with the correct subnet for the changes to take effect.
Steps to Enable Internet Access
- Attach an Internet Gateway to the VPC.
- Open the Route Table linked to the public subnet.
- Add a route:
- Destination:
0.0.0.0/0(IPv4) and/or::/0(IPv6) - Target: The Internet Gateway ID (e.g.,
igw-xxxxxxxx)
- Ensure the subnet’s EC2 instances have a public IP or Elastic IP assigned.
Example
If your public subnet’s CIDR block is
10.0.1.0/24:- Route to VPC:
10.0.0.0/16 → local(default)
- Route to Internet:
0.0.0.0/0 → igw-12345678