Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company wants to peer a new spoke virtual network with an existing hub VNet. The hub uses 10.20.0.0/16. The spoke was created with 10.20.1.0/24 because that range was still available in the IPAM spreadsheet. VNet peering creation fails. What should the administrator do first?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Enable gateway transit on the hub and retry the peering.
Gateway transit helps spokes use a hub gateway, but it does not resolve overlapping address spaces.
B
Distractor review
Add a route table to the spoke subnet so the networks can communicate.
User-defined routes affect packet forwarding after connectivity exists; they do not fix overlapping CIDR blocks.
C
Best answer
Change the spoke VNet address space to a non-overlapping range, then recreate or update peering.
VNet peering requires the two virtual networks to have non-overlapping IP address spaces. Because the hub already uses 10.20.0.0/16, the spoke cannot use 10.20.1.0/24. The administrator must renumber the spoke to a different range, such as 10.21.0.0/16 or another approved block, before peering can succeed.
D
Distractor review
Configure a custom DNS server in the spoke to translate the overlapping range.
DNS can help name resolution, but it cannot make overlapping network ranges eligible for peering.
Common exam trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
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More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A route table contains these entries: 10.0.0.0/8 with next hop Virtual appliance, and 10.1.1.0/24 with next hop Virtual network gateway. Which next hop will Azure use for traffic to 10.1.1.5?
Question 2
You are deploying a stateless web application on Azure virtual machines. The solution must automatically add and remove instances based on CPU demand and allow all instances to be managed as one logical group. Which Azure compute feature should you deploy?
Question 3
You are deploying a Windows Server VM for an internal app. The VM must support Secure Boot and vTPM later, its OS disk must survive host moves, and the team wants the lowest-cost managed disk tier that still behaves like a normal writable OS disk. Which two choices should you make? Select two.
Question 4
You need to deploy several identical virtual machines and ensure that the failure of a single Azure host does not affect all of them. Which feature should you use?
Question 5
You need to connect VNet-Hub and VNet-Spoke so that resources in both virtual networks can communicate privately over the Microsoft backbone. Both virtual networks are in the same region. What should you configure?
Question 6
You need to create a storage account that provides the lowest-cost redundant storage for non-critical data and only needs protection against local disk or server failure within a single datacenter. Which redundancy option should you choose?
FAQ
Questions learners often ask
What does this AZ-104 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: Change the spoke VNet address space to a non-overlapping range, then recreate or update peering. — Azure VNet peering only works when the two VNets use distinct, non-overlapping address spaces. In this case, 10.20.1.0/24 sits inside the hub’s 10.20.0.0/16 range, so peering is rejected before routing or DNS settings matter. The correct remediation is to renumber the spoke to an available, non-overlapping CIDR block and then establish the peering relationship. Why others are wrong: Gateway transit is for allowing spokes to use a hub’s gateway services and does not solve address conflicts. Route tables also do not override the peering validation step. DNS configuration only affects name resolution, not IP range uniqueness. The failure happens because of overlapping CIDRs, so the address space itself must change.
What should I do if I get this AZ-104 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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