You will now review the Route Tables in use by the lab EC2 instances
Route Table configuration
- Collect the output values from your CloudFormation stack for PrivateSubnet1ARouteTable and PrivateSubnet2ARouteTable. These are the route tables associated with your private subnets and affect the routing behavior of your EC2 instances; Sales App and Reports Engine.
- Access the Route table screen in the VPC dashboard in the AWS console at the following URL: https://us-east-1.console.aws.amazon.com/vpc/home?region=us-east-1#RouteTables:sort=routeTableId
- Highlight one of the private route tables and examine the route table entries. Notice that an immutable entry with a prefix list (format pl-xxx) entry has been populated in the route table and its target is the gateway vpc endpoint. This entry is automatically populated by AWS when a gateway endpoint is created and associated with a subnet. The prefix list ID logically represents the range of public IP addresses used by the service. All instances in subnets associated with the specified route tables automatically use the endpoint to access the service. Subnets that are not associated with the specified route tables do not use the endpoint. This enables you to keep resources in other subnets separate from your endpoint. To view the current public IP address range for a service, you can use the describe-prefix-lists command from the aws cli. For more information see: https://docs.aws.amazon.com/vpc/latest/userguide/vpce-gateway.html#vpc-endpoints-routing