AZ-104 Question 200
Single answerYou have created a new virtual network (VNet) in Azure with an address space of 10.1.0.0/16. The VNet already includes a 'FrontEnd' subnet with a 10.1.0.0/24 address range for web servers. You need to add a 'BackEnd' subnet for database servers, but you receive an error when you try to assign 10.1.0.0/24 to the 'BackEnd' subnet because of overlapping address ranges. How can you successfully create the 'BackEnd' subnet?
- A
Modify the existing FrontEnd subnet from 10.1.0.0/24 to 10.1.1.0/24 and keep the BackEnd subnet as 10.1.0.0/24
- B
Expand the entire VNet address space to 10.1.0.0/8 so the subnets no longer overlap
- C
Use a non-overlapping address range such as 10.1.1.0/24 for the BackEnd subnet
- D
Reduce the FrontEnd subnet to 10.1.0.0/25 and use the remaining 10.1.0.128/25 block for the BackEnd subnet
Show answer and explanation
Correct answer: C
Explanation
The root cause of the error is that the proposed BackEnd subnet range overlaps with the existing FrontEnd subnet range. By selecting a non-overlapping range like 10.1.1.0/24 for the BackEnd, both subnets fit within the 10.1.0.0/16 VNet address space without conflict or additional complexity.
- A. Incorrect.
Changing the FrontEnd subnet to 10.1.1.0/24 and placing the BackEnd subnet on 10.1.0.0/24 does not address the current overlap; you would still have to delete and recreate subnets, and this approach can be disruptive.
- B. Incorrect.
Expanding the VNet address space from /16 to /8 would give you more address space than needed and is generally not best practice due to potential IP addressing conflicts and future complexities.
- C. Correct.
Using 10.1.1.0/24 provides a non-overlapping subnet range within the existing 10.1.0.0/16 address space, allowing you to create both subnets without conflict.
- D. Incorrect.
Splitting the FrontEnd subnet into two smaller subnets can create unnecessary complexity and requires reassigning IP addresses and reconfiguring services, making it less efficient than simply choosing a different /24 range for the BackEnd.