Maximum and Minimum IP Addresses for AWS VPC Subnets
Question
When you create a subnet, you specify the CIDR block for the subnet.
The CIDR block of a subnet can be the same as the CIDR block for the VPC (for a single subnet in the VPC), or a subset (to enable multiple subnets)
The allowed block size is between a /28 netmask and /16 netmask.
You decide to you create a VPC with CIDR block 10.0.0.0/24
Therefore what is the maximum allowed number of IP addresses and the minimum allowed number of IP addresses according to AWS and what is the number of IP addresses supported by the VPC you created? Choose the correct answer from the options below.
Answers
Explanations
Click on the arrows to vote for the correct answer
A. B. C. D.Answer - D.
This is clearly given in the aws documentation.
For more information on VPC and subnets please see the below link:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Subnets.html
When creating a subnet in AWS, you must specify the CIDR block for the subnet. The CIDR block determines the range of IP addresses that are available in the subnet. In this case, we have created a VPC with CIDR block 10.0.0.0/24.
The CIDR block for a subnet can be the same as the CIDR block for the VPC, or it can be a subset of the VPC CIDR block. However, the allowed block size for a subnet is between a /28 netmask and a /16 netmask.
The number of IP addresses that can be assigned to a subnet is determined by the CIDR block. The formula to calculate the number of IP addresses in a CIDR block is:
2^(32 - netmask)
where netmask is the number of bits in the subnet mask. For example, a /24 netmask has 24 bits set to 1, so the number of IP addresses is:
2^(32-24) = 2^8 = 256
Therefore, a /24 CIDR block can support up to 256 IP addresses.
To answer the question, we need to determine the maximum and minimum number of IP addresses allowed for a subnet, and the number of IP addresses supported by the VPC we created.
The maximum and minimum number of IP addresses allowed for a subnet are determined by the allowed block size, which is between a /28 netmask and a /16 netmask.
- The maximum allowed netmask is /16, which gives us a maximum of 2^(32-16) = 65,536 IP addresses.
- The minimum allowed netmask is /28, which gives us a minimum of 2^(32-28) = 16 IP addresses.
Therefore, the correct answer is D. The maximum number of IP addresses is 65,536, the minimum number of IP addresses is 16, and the VPC we created supports 256 IP addresses.