Which factors could cause this error?

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In: SAP-C02
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A software company hosts an application on AWS with resources in multiple AWS accounts and Regions.The application runs on a group of Amazon EC2 instances in an application VPC located in the us-east-1 Region with an IPv4 CIDR block of 10.10.0.0/16.In a different AWS account, a shared services VPC is located in the us-east-2 Region with an IPv4 CIDR block of 10.10.10.0/24.When a cloud engineer uses AWS CloudFormation to attempt to peer the application VPC with the shared services VPC, an error message indicates a peering failure.

Which factors could cause this error?

(Choose two.)

The IPv4 CIDR ranges of the two VPCs overlap

The VPCs are not in the same Region

One or both accounts do not have access to an Internet gateway

One of the VPCs was not shared through AWS Resource Access Manager

The IAM role in the peer accepter account does not have the correct permissions

Explanations:

VPC peering requires non-overlapping CIDR blocks. The CIDR blocks 10.10.0.0/16 and 10.10.10.0/24 overlap, causing the peering failure.

VPC peering supports connections across Regions, so VPCs do not need to be in the same Region for peering.

An Internet Gateway is not required for VPC peering; it is only necessary for public internet access.

AWS Resource Access Manager (RAM) is not needed to peer VPCs across accounts; RAM is used for sharing resources within or across accounts.

The IAM role in the peer accepter account needs specific permissions to accept the peering request; lacking permissions can cause the failure.

2025-10-17

1 Comment

  1. Stephanie
    Author

    I believe the answer is:
    The IPv4 CIDR ranges of the two VPCs overlap

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