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

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.

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.

    When this WOULD be correct

    In a scenario where the hub VNet is configured as a network virtual appliance (NVA) with IP forwarding enabled, and user-defined routes (UDRs) are applied to the spoke subnets to force traffic through the NVA, then spoke-to-spoke traffic can flow through the hub.

  • 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.

    When this WOULD be correct

    If the question asked about using Azure Firewall or Network Virtual Appliances to filter traffic between VNets with overlapping IPs, then placing them in separate resource groups might be acceptable as they are not peered directly.

  • 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.

    When this WOULD be correct

    If the question described a hub VNet with a VPN gateway configured for BGP and the spokes were connected via gateway transit (enabled on the peering), then traffic between spokes could be routed automatically through the hub without additional UDRs.

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.

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

Why this is correct

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

VNet peering is transitive, so spoke-to-spoke traffic will automatically use the hub peering.Wrong answer — click to see why

Why this is wrong here

VNet peering is non-transitive; a peered connection between VNet-A and the hub, and between VNet-B and the hub, does not automatically enable direct traffic between VNet-A and VNet-B through the hub.

★ When this WOULD be the correct answer

In a scenario where the hub VNet is configured as a network virtual appliance (NVA) with IP forwarding enabled, and user-defined routes (UDRs) are applied to the spoke subnets to force traffic through the NVA, then spoke-to-spoke traffic can flow through the hub.

Why candidates choose this

Candidates often confuse the transitive nature of on-premises routing with Azure VNet peering, which is non-transitive by default, leading them to assume that hub-and-spoke peering automatically enables spoke-to-spoke communication.

Overlapping CIDR blocks are allowed if the VNets are placed in separate resource groups.Wrong answer — click to see why

Why this is wrong here

Overlapping CIDR blocks are not allowed for VNet peering even if VNets are in separate resource groups; peering requires non-overlapping address spaces.

★ When this WOULD be the correct answer

If the question asked about using Azure Firewall or Network Virtual Appliances to filter traffic between VNets with overlapping IPs, then placing them in separate resource groups might be acceptable as they are not peered directly.

Why candidates choose this

Candidates may think resource group isolation allows overlapping IPs, but Azure enforces address space uniqueness for peering regardless of resource group or subscription.

If the hub has a VPN gateway, spoke traffic to other spokes is routed automatically without additional configuration.Wrong answer — click to see why

Why this is wrong here

In Azure, VNet peering is non-transitive; traffic from one spoke to another must be explicitly routed through a hub, typically using a network virtual appliance or gateway transit. A VPN gateway in the hub does not automatically route spoke-to-spoke traffic without additional configuration like user-defined routes.

★ When this WOULD be the correct answer

If the question described a hub VNet with a VPN gateway configured for BGP and the spokes were connected via gateway transit (enabled on the peering), then traffic between spokes could be routed automatically through the hub without additional UDRs.

Why candidates choose this

Candidates may assume that a VPN gateway in the hub acts as a central router that automatically forwards traffic between connected spokes, similar to a traditional hub-and-spoke topology in on-premises networks.

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?”

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.

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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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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.