A user has created a VPC with CIDR 20.0.0.0/24. The user has created a public subnet with CIDR 20.0.0.0/25.
The user is trying to create the private subnet with CIDR 20.0.0.128/25. Which of the below mentioned
statements is true in this scenario?
A.
It will not allow the user to create the private subnet due to a CIDR overlap
B.
It will allow the user to create a private subnet with CIDR as 20.0.0.128/25
C.
This statement is wrong as AWS does not allow CIDR 20.0.0.0/25
D.
It will not allow the user to create a private subnet due to a wrong CIDR range
Explanation:
When the user creates a subnet in VPC, he specifies 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.. If the user creates more than one subnet in a VPC, the CIDR blocks of the subnets must not overlap.
Thus, in this case the user has created a VPC with the CIDR block 20.0.0.0/24, which supports 256 IP addresses
(20.0.0.0 to 20.0.0.255.. The user can break this CIDR block into two subnets, each supporting 128 IP
addresses. One subnet uses the CIDR block 20.0.0.0/25 (for addresses 20.0.0.0 – 20.0.0.127. and the other uses
the CIDR block 20.0.0.128/25 (for addresses 20.0.0.128 – 20.0.0.255..