AWS Certified Advanced Networking Specialty Practice Exam

To allow VPC Y's instances to communicate with instances in VPC X and VPC Z, what should be done based on the given peering setup?

1. Create one route table for both connections

2. Use NAT instances for routing

3. Create two route tables for destinations X and Z

4. Use AWS Transit Gateway

The correct answer is: Create two route tables for destinations X and Z

In a scenario where instances in VPC Y need to communicate with instances in both VPC X and VPC Z through VPC peering, setting up two route tables for the specific destinations is essential. Each route table can manage the routes for its respective VPC peering connection, ensuring that outbound traffic is correctly directed. When VPC Y's route table is configured for both VPC X's and VPC Z's CIDR blocks, it simplifies the traffic routing. Specifically, one route can direct traffic destined for VPC X while another can handle traffic for VPC Z. This approach allows the network flow to be managed independently for each VPC, which is crucial when there might be different CIDR ranges or if unique routing policies are applied. Utilizing a single route table for both connections could lead to potential conflicts or misdirection, especially in more complex networking setups. Furthermore, NAT instances would not typically facilitate VPC-to-VPC traffic; they are primarily used for outbound internet traffic from private subnets. An AWS Transit Gateway could provide a more scalable solution for larger architectures involving many VPCs but may not be necessary in simpler setups with just a few VPCs. Thus, creating two distinct route tables for the individual destinations provides