Questions 25 to 27

Explanations for questions 25 to 27

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Question 25

An Amazon EC2 instance has been launched into an Amazon VPC. A solutions architect needs to ensure that instances have both a private and public DNS hostnames. Assuming settings were not changed during the creation of the VPC, how will DNS hostnames be assigned by default? (Select TWO)

  1. In all VPCs instances, no DNS hostnames will be assigned.
  2. In non-default VPC, instances will be assigned a public and private DNS hostname.
  3. In default VPC, instances will be assigned a public and private DNS hostname.
  4. In a non-default VPC, instances will be assigned a private but not a public DNS hostname.
  5. In a default VPC, instances will be assigned a private but not a public DNS hostname.

Correct Answer: 3, 4

Explanation: When you launch an instance into a default VPC, your instance is provided with public and private DNS hostnames that correspond to the public IPv4 and private IPv4 addresses for the instance.

When you launch an instance into a nondefault VPC, your instance is provided with a private DNS hostname. Depending on the DNS attributes you specify for the VPC and if your instance has a public IPv4 address, it might be provided a public DNS hostname.

All other statements are incorrect with default settings.

INCORRECT:In all VPCs instances, no DNS hostnames will be assigned.” is incorrect as explained above.

INCORRECT:In a non-default VPC, instances will be assigned a public and private DNS hostname.” is incorrect as explained above.

CORRECT: “In a default VPC, instances will be assigned a public and private DNS hostname.” is the correct answer.

CORRECT: “In a non-default VPC, instances will be assigned a private but not a public DNS hostname.” is the correct answer.

INCORRECT:In a default VPC, instances will be assigned a private but not a public DNS hostname.” is incorrect as explained above.

References: https://docs.aws.amazon.com/vpc/latest/userguide/vpc-dns.html

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