Elastic Network Interface Public IP Addresses | AWS Certified Advanced Networking - Specialty

How Many Public IP Addresses Can Be Assigned to an Elastic Network Interface?

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Question

How many public IP addresses can be assigned to an Elastic Network interface? Choose one answer from the options given below.

Answers

Explanations

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A. B. C. D.

Answer - A.

A network interface can include the following attributes:

A primary private IPv4 address.

One or more secondary private IPv4 addresses.

One Elastic IP address (IPv4) per private IPv4 address.

One public IPv4 address.

One or more IPv6 addresses.

One or more security groups.

A MAC address.

A source/destination check flag.

A description.

For more information on the Elastic Network Interface, please visit the below link:

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html

An Elastic Network Interface (ENI) is a virtual network interface that can be attached to an EC2 instance in a VPC. An ENI can have one or more private IP addresses, and it can also have one or more public IP addresses, depending on how it is configured.

Regarding the number of public IP addresses that can be assigned to an ENI, the answer is:

A. 1

By default, when you launch an EC2 instance in a VPC, it is assigned a private IP address from the VPC subnet. If you want your instance to be accessible from the Internet, you can associate an Elastic IP address (EIP) with the instance's primary network interface (eth0). An EIP is a static, public IP address that you can allocate from AWS and attach to your instance. However, an ENI can have only one EIP associated with it at a time. If you want to associate multiple public IP addresses with an ENI, you can use an IP alias, but the primary IP address must be an EIP.

In conclusion, the correct answer is A. 1.