Question 491 of 1,170
Implement and Manage Virtual NetworkinghardMultiple SelectObjective-mapped

Quick Answer

The correct answer is that VNet peering with overlapping address spaces is not allowed in Azure, and to route traffic between spoke VNets through a hub, you must implement an explicit design like gateway transit or custom routing. This is because Azure requires the address spaces of peered VNets to be unique and non-overlapping; in this case, VNet-A’s 10.20.0.0/16 fully contains VNet-B’s 10.20.128.0/17, making the peering request invalid until one range is changed. On the AZ-104 exam, this scenario tests your understanding of both VNet peering constraints and hub-spoke topology requirements—a common trap is assuming that simply peering all VNets to the hub will automatically route spoke-to-spoke traffic through it, but without gateway transit or user-defined routes, traffic will attempt direct peering or fail. Remember the memory tip: “No overlap, no direct spoke-to-spoke—route through the hub with transit or UDRs.”

AZ-104 Implement and Manage Virtual Networking Practice Question

This AZ-104 practice question tests your understanding of implement and manage virtual networking. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

Two virtual networks are in different subscriptions. VNet-A uses 10.20.0.0/16 and VNet-B uses 10.20.128.0/17. A design review also states that traffic between two spoke VNets should flow through a hub VNet instead of directly between spokes. Which two statements are correct? Select two.

Question 1hardmulti select
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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

The two VNets cannot be peered until one address space is changed because the ranges overlap.

Option A is correct because VNet peering in Azure requires that the address spaces of the peered VNets do not overlap. VNet-A uses 10.20.0.0/16 and VNet-B uses 10.20.128.0/17, which are overlapping ranges (10.20.128.0/17 is a subset of 10.20.0.0/16). Azure will reject the peering request until one of the address spaces is changed to eliminate the overlap.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • The two VNets cannot be peered until one address space is changed because the ranges overlap.

    Why this is correct

    Azure peering does not allow overlapping address spaces, even across subscriptions.

    Related concept

    Read the scenario before looking for a memorised answer.

  • VNet peering is transitive, so spoke-to-spoke traffic will automatically use the hub peering.

    Why it's wrong here

    Peering is nontransitive, so one peering does not automatically connect other peerings together.

  • To reach another spoke through the hub, you need an explicit design such as gateway transit or routing controls.

    Why this is correct

    A hub-and-spoke architecture needs deliberate routing or gateway design to carry traffic between spokes.

    Related concept

    Read the scenario before looking for a memorised answer.

  • Overlapping CIDR blocks are allowed if the VNets are placed in separate resource groups.

    Why it's wrong here

    Resource group boundaries do not change the overlap restriction for virtual network address spaces.

  • If the hub has a VPN gateway, spoke traffic to other spokes is routed automatically without additional configuration.

    Why it's wrong here

    A gateway alone does not make peering transitive or create spoke-to-spoke reachability by default.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often assume VNet peering is transitive (like in some other cloud providers) or that a VPN gateway automatically routes spoke-to-spoke traffic, but Azure requires explicit routing configuration for transitive traffic through a hub.

Detailed technical explanation

How to think about this question

Azure VNet peering is a non-transitive, one-to-one connection. For hub-and-spoke topologies, you must explicitly configure routing, typically by deploying a network virtual appliance (NVA) or using Azure Route Server, and then add user-defined routes (UDRs) on each spoke subnet to force traffic to the hub. The overlapping address space issue is enforced by Azure's network resource provider, which validates CIDR ranges during peering creation; RFC 1918 private address spaces are checked for any overlap, even if the VNets are in different subscriptions or regions.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A healthcare organisation deploys an application with a public-facing web tier and a private database tier. The database subnet has no public IP and only accepts connections from the web tier's security group. Questions like this test whether you can design cloud network isolation using VNets/VPCs, subnets, and security group rules.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Related practice questions

Related AZ-104 practice-question pages

Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.

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FAQ

Questions learners often ask

What does this AZ-104 question test?

Implement and Manage Virtual Networking — This question tests Implement and Manage Virtual Networking — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The two VNets cannot be peered until one address space is changed because the ranges overlap. — Option A is correct because VNet peering in Azure requires that the address spaces of the peered VNets do not overlap. VNet-A uses 10.20.0.0/16 and VNet-B uses 10.20.128.0/17, which are overlapping ranges (10.20.128.0/17 is a subset of 10.20.0.0/16). Azure will reject the peering request until one of the address spaces is changed to eliminate the overlap.

What should I do if I get this AZ-104 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Same concept, more angles

1 more ways this is tested on AZ-104

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. A new spoke virtual network will peer with an existing hub that uses 10.10.0.0/16 and an on-premises network that uses 10.20.0.0/16. Which two address spaces could you assign to the new spoke without overlapping those ranges? Select two.

easy
  • A.10.11.0.0/16
  • B.10.10.128.0/17
  • C.192.168.50.0/24
  • D.10.20.1.0/24
  • E.10.10.1.0/24

Why A: Option A (10.11.0.0/16) is correct because it is a distinct subnet within the private 10.0.0.0/8 range that does not overlap with the hub's 10.10.0.0/16 or the on-premises 10.20.0.0/16. Azure virtual network peering requires non-overlapping address spaces to enable direct routing between resources without conflict.

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Last reviewed: Jun 11, 2026

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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.