<note> <p>We are retiring EC2-Classic. We recommend that you migrate from EC2-Classic to a VPC. For more information, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/vpc-migrate.html">Migrate from EC2-Classic to a VPC</a> in the <i>Amazon Elastic Compute Cloud User Guide</i>.</p> </note> <p>Enables a VPC to support DNS hostname resolution for ClassicLink. If enabled, the DNS hostname of a linked EC2-Classic instance resolves to its private IP address when addressed from an instance in the VPC to which it's linked. Similarly, the DNS hostname of an instance in a VPC resolves to its private IP address when addressed from a linked EC2-Classic instance. For more information, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/vpc-classiclink.html">ClassicLink</a> in the <i>Amazon Elastic Compute Cloud User Guide</i>.</p> <p>You must specify a VPC ID in the request.</p>