AZ-104 Implement and Manage Virtual Networking Practice Question
A company wants to peer two Azure virtual networks so that workloads can communicate privately. VNet-A uses 10.10.0.0/16. VNet-B is being designed now. Which address space should be chosen for VNet-B?
⚠ Common exam trap
Candidates often assume smaller subnets within the same larger range can be peered because they are 'different subnets,' but Azure VNet peering requires completely non-overlapping address spaces at the VNet level, not just at the subnet level.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
10.11.0.0/16, because it does not overlap and is still within a private IPv4 range.
VNet peering requires non-overlapping address spaces to enable direct private IP connectivity between resources. 10.11.0.0/16 is a unique private IPv4 range (RFC 1918) that does not overlap with VNet-A's 10.10.0.0/16, ensuring successful peering without routing conflicts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
10.10.5.0/24, because it is a smaller subnet inside the same private range.
Why it's wrong here
10.10.5.0/24 is not a separate, independent block; it is a subnet carved out of the 10.10.0.0/16 that VNet-A already uses. Azure's VNet peering validation compares the complete address space prefixes, not the individual subnets you might deploy, so any overlap—even a smaller subnet inside a larger range—makes peering impossible. This answer fails because the address space is contained within the other VNet's CIDR, not because of the subnet mask.
When this WOULD be correct
If the question asked for a subnet within VNet-A (e.g., 'Which subnet should be used for a new application in VNet-A?'), then 10.10.5.0/24 would be a valid choice as it falls within the VNet's address space.
- ✓
10.11.0.0/16, because it does not overlap and is still within a private IPv4 range.
Why this is correct
10.11.0.0/16 does not overlap with VNet-A's 10.10.0.0/16 and sits fully within the RFC 1918 private address space. That makes it a valid address space for a peered VNet because Azure VNet peering only requires that the full CIDR ranges of the two VNets are non-overlapping; it does not require any specific prefix or class. Choosing a distinct /16 also leaves plenty of room for subnets without risk of future overlap conflicts.
- ✗
10.10.0.0/24, because peering automatically separates overlapping subnets.
Why it's wrong here
Azure never automatically separates or translates overlapping subnets during peering; the peering connection simply creates a routing relationship between the two VNets' address spaces. 10.10.0.0/24 falls inside 10.10.0.0/16, and even though the subnet masks differ, Azure blocks the peering because the ranges are considered overlapping. You cannot use more specific prefixes to bypass this restriction, as no address translation is performed in a VNet peering.
When this WOULD be correct
If the question asked about adding a subnet to VNet-A (not peering a new VNet), then 10.10.0.0/24 would be a valid subnet within the existing VNet-A address space.
- ✗
192.168.1.0/24, because peered networks must always use the 192.168.x.x range.
Why it's wrong here
The assertion that peered networks must always use the 192.168.x.x range is simply false; Azure accepts any private IP range that does not collide with the other VNet's address space. While 192.168.1.0/24 might be valid if the other VNet uses a different range, the stated justification is the reason this answer is wrong. The actual rule for peering is non-overlap, not a mandated RFC 1918 class or private block.
When this WOULD be correct
If the question stated that the company's on-premises network uses 10.0.0.0/8 and 172.16.0.0/12, and they want to avoid any conflict with existing routes, then using 192.168.1.0/24 could be correct to ensure no overlap with on-premises ranges.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-104 exam frequently reuses these exact scenarios with slightly different constraints.
✓10.11.0.0/16, because it does not overlap and is still within a private IPv4 range.Correct answer▾
Why this is correct
10.11.0.0/16 does not overlap with VNet-A's 10.10.0.0/16 and sits fully within the RFC 1918 private address space. That makes it a valid address space for a peered VNet because Azure VNet peering only requires that the full CIDR ranges of the two VNets are non-overlapping; it does not require any specific prefix or class. Choosing a distinct /16 also leaves plenty of room for subnets without risk of future overlap conflicts.
✗10.10.5.0/24, because it is a smaller subnet inside the same private range.Wrong answer — click to see why▾
Why this is wrong here
VNet-B's address space 10.10.5.0/24 overlaps with VNet-A's 10.10.0.0/16, which is not allowed for peering. Azure requires non-overlapping address spaces for virtual network peering.
★ When this WOULD be the correct answer
If the question asked for a subnet within VNet-A (e.g., 'Which subnet should be used for a new application in VNet-A?'), then 10.10.5.0/24 would be a valid choice as it falls within the VNet's address space.
Why candidates choose this
Candidates may think that using a smaller subnet from the same range is acceptable, or they confuse subnetting within a VNet with the requirement for non-overlapping address spaces between peered VNets.
✗10.10.0.0/24, because peering automatically separates overlapping subnets.Wrong answer — click to see why▾
Why this is wrong here
VNet-A uses 10.10.0.0/16, which includes the 10.10.0.0/24 range. Overlapping address spaces prevent successful peering because Azure cannot route between overlapping IPs.
★ When this WOULD be the correct answer
If the question asked about adding a subnet to VNet-A (not peering a new VNet), then 10.10.0.0/24 would be a valid subnet within the existing VNet-A address space.
Why candidates choose this
Candidates may mistakenly believe that peering automatically handles overlapping ranges or that smaller subnets can be used without conflict, ignoring the fundamental requirement of non-overlapping address spaces for VNet peering.
✗192.168.1.0/24, because peered networks must always use the 192.168.x.x range.Wrong answer — click to see why▾
Why this is wrong here
Peered Azure virtual networks can use any private IP address range (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) as long as they do not overlap. There is no requirement to use 192.168.x.x.
★ When this WOULD be the correct answer
If the question stated that the company's on-premises network uses 10.0.0.0/8 and 172.16.0.0/12, and they want to avoid any conflict with existing routes, then using 192.168.1.0/24 could be correct to ensure no overlap with on-premises ranges.
Why candidates choose this
Candidates may mistakenly believe that Azure requires peered networks to use the 192.168.x.x range, possibly confusing it with common home network setups or outdated documentation.
Analysis generated from the official AZ-104blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
Managed Identities for Azure Resources
Key term
VNet
A virtual private network inside a cloud provider that lets you securely connect and isolate your cloud resources.
Key term
VNet peering
VNet peering is a networking connection that links two virtual networks so they can communicate with each other as if they were a single network.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-104 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-104 exam.