Question 258 of 1,170

Implement and Manage Virtual Networking →hardMultiple SelectObjective-mapped

How Azure Route Selection Uses Longest Prefix Match for UDRs

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. A key principle to apply: azure route tables use the longest prefix match to determine the next hop.. 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.

A subnet has a route table with these user-defined routes: 10.10.0.0/16 to Virtual appliance, 10.10.5.0/24 to Virtual network gateway, and 10.10.5.128/25 to Virtual network. The subnet is attached to a VM that sends traffic to several destinations. Which three next-hop decisions are correct? Select three.

A
Traffic to 10.10.5.9 uses Virtual network gateway.
The /24 route is more specific than the broader /16 route, so it wins for 10.10.5.9.
B
Traffic to 10.10.5.200 uses Virtual network.
The /25 route is the most specific match for 10.10.5.200, so it takes precedence.
C
Traffic to 10.10.8.4 uses Virtual appliance.
The destination matches only the broader 10.10.0.0/16 route, which points to the appliance.
D
Traffic to 10.10.5.9 uses Virtual appliance.
Why wrong: A more specific /24 route exists, so the broader /16 next hop is not chosen.
E
Traffic to 8.8.8.8 uses Virtual appliance.
Why wrong: No 10.10.x.x route matches 8.8.8.8, so the default system route would apply instead.

Full breakdown with real-world context →

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

✓

Traffic to 10.10.5.9 uses Virtual network gateway.

Option A is correct because the route table uses longest prefix match. The destination 10.10.5.9 falls within the 10.10.5.0/24 range, which has a more specific prefix (24 bits) than 10.10.0.0/16 (16 bits). The user-defined route for 10.10.5.0/24 specifies a next hop of Virtual network gateway, so traffic to 10.10.5.9 is forwarded to the gateway.

Key principle: Azure route tables use the longest prefix match to determine the next hop.

Answer analysis

Option-by-option breakdown

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

✓
Traffic to 10.10.5.9 uses Virtual network gateway.
Why this is correct
The /24 route is more specific than the broader /16 route, so it wins for 10.10.5.9.
Related concept
Azure route tables use the longest prefix match to determine the next hop.
✓
Traffic to 10.10.5.200 uses Virtual network.
Why this is correct
The /25 route is the most specific match for 10.10.5.200, so it takes precedence.
Related concept
Azure route tables use the longest prefix match to determine the next hop.
✓
Traffic to 10.10.8.4 uses Virtual appliance.
Why this is correct
The destination matches only the broader 10.10.0.0/16 route, which points to the appliance.
Related concept
Azure route tables use the longest prefix match to determine the next hop.
✗
Traffic to 10.10.5.9 uses Virtual appliance.
Why it's wrong here
A more specific /24 route exists, so the broader /16 next hop is not chosen.
When this WOULD be correct
If the route table did not include the 10.10.5.0/24 route, or if the Virtual appliance route had a longer prefix match (e.g., 10.10.5.0/25) that included 10.10.5.9, then traffic to 10.10.5.9 would use the Virtual appliance.
✗
Traffic to 8.8.8.8 uses Virtual appliance.
Why it's wrong here
No 10.10.x.x route matches 8.8.8.8, so the default system route would apply instead.
When this WOULD be correct
If the route table included a user-defined route 0.0.0.0/0 with next hop Virtual appliance, then traffic to 8.8.8.8 would use the Virtual appliance.

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.

✓Traffic to 10.10.5.9 uses Virtual network gateway.Correct answer▾

Why this is correct

The /24 route is more specific than the broader /16 route, so it wins for 10.10.5.9.

✗Traffic to 10.10.5.9 uses Virtual appliance.Wrong answer — click to see why▾

Why this is wrong here

The route table has a more specific route for 10.10.5.0/24 to Virtual network gateway, which matches 10.10.5.9 exactly, so traffic uses the gateway, not the Virtual appliance.

★ When this WOULD be the correct answer

If the route table did not include the 10.10.5.0/24 route, or if the Virtual appliance route had a longer prefix match (e.g., 10.10.5.0/25) that included 10.10.5.9, then traffic to 10.10.5.9 would use the Virtual appliance.

Why candidates choose this

Candidates may mistakenly think that the Virtual appliance route (10.10.0.0/16) covers 10.10.5.9 and is the most specific, ignoring the more specific 10.10.5.0/24 route.

✗Traffic to 8.8.8.8 uses Virtual appliance.Wrong answer — click to see why▾

Why this is wrong here

The route table does not have a default route (0.0.0.0/0) pointing to the Virtual appliance; traffic to 8.8.8.8 (internet) would use the system default route (Internet) or fail if no default route exists.

★ When this WOULD be the correct answer

If the route table included a user-defined route 0.0.0.0/0 with next hop Virtual appliance, then traffic to 8.8.8.8 would use the Virtual appliance.

Why candidates choose this

Candidates may assume that a Virtual appliance can handle all non-VNet traffic, but without a default route, it won't be used for internet destinations.

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 a broader route (like 10.10.0.0/16 to Virtual appliance) applies to all subnets, forgetting that more specific user-defined routes (like 10.10.5.0/24 to Virtual network gateway) take precedence via longest prefix match, and that public IPs like 8.8.8.8 are not matched by private address space routes.

Detailed technical explanation

How to think about this question

Azure route tables evaluate routes using longest prefix match (LPM) with a preference order: user-defined routes (UDRs) override system routes for matching prefixes, but more specific prefixes always win regardless of route type. The 10.10.5.128/25 route is a subset of 10.10.5.0/24, so traffic to 10.10.5.200 (which falls in 10.10.5.128/25) uses the Virtual network next hop, while traffic to 10.10.5.9 (outside that /25) uses the /24 route. For non-matching destinations, Azure falls back to system routes (e.g., Internet for 0.0.0.0/0), not the Virtual appliance.

KKey Concepts to Remember

Azure route tables use the longest prefix match to determine the next hop.
A /24 route is more specific than a /16 route for an overlapping IP address.
User-defined routes (UDRs) override default system routes for matching traffic.
Traffic not matching any UDR will follow Azure's default routing rules.

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

Azure route tables use the longest prefix match to determine the next hop.

Real-world example

How this comes up in practice

An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.

Visual reference

What to study next

Got this wrong? Here's your next step.

Review azure route tables use the longest prefix match to determine the next hop., then practise related AZ-104 questions on the same topic to reinforce the concept.

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.

Manage Azure Identities and Governance practice questions

Practise AZ-104 questions linked to Manage Azure Identities and Governance.

Implement and Manage Storage practice questions

Practise AZ-104 questions linked to Implement and Manage Storage.

Deploy and Manage Azure Compute practice questions

Practise AZ-104 questions linked to Deploy and Manage Azure Compute.

Implement and Manage Virtual Networking practice questions

Practise AZ-104 questions linked to Implement and Manage Virtual Networking.

Monitor and Maintain Azure Resources practice questions

Practise AZ-104 questions linked to Monitor and Maintain Azure Resources.

AZ-104 Azure RBAC practice questions

Practise AZ-104 questions linked to AZ-104 Azure RBAC.

AZ-104 storage account practice questions

Practise AZ-104 questions linked to AZ-104 storage account.

AZ-104 virtual network practice questions

Practise AZ-104 questions linked to AZ-104 virtual network.

AZ-104 NSG practice questions

Practise AZ-104 questions linked to AZ-104 NSG.

AZ-104 Azure Monitor practice questions

Practise AZ-104 questions linked to AZ-104 Azure Monitor.

AZ-104 backup practice questions

Practise AZ-104 questions linked to AZ-104 backup.

AZ-104 managed identity practice questions

Practise AZ-104 questions linked to AZ-104 managed identity.

Practice this exam

Start a free AZ-104 practice session

Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.

10 questions 20 questions 30 questions 50 questions Timed 30

AZ-104 practice-test guide →Study guide →Browse all practice tests

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 — Azure route tables use the longest prefix match to determine the next hop..

What is the correct answer to this question?

The correct answer is: Traffic to 10.10.5.9 uses Virtual network gateway. — Option A is correct because the route table uses longest prefix match. The destination 10.10.5.9 falls within the 10.10.5.0/24 range, which has a more specific prefix (24 bits) than 10.10.0.0/16 (16 bits). The user-defined route for 10.10.5.0/24 specifies a next hop of Virtual network gateway, so traffic to 10.10.5.9 is forwarded to the gateway.

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

Review azure route tables use the longest prefix match to determine the next hop., then practise related AZ-104 questions on the same topic to reinforce the concept.

What is the key concept behind this question?

Azure route tables use the longest prefix match to determine the next hop.

About these practice questions

Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →

How Courseiva writes practice questions · Editorial policy

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 subnet has a route table with these user-defined routes: 172.16.0.0/16 -> Virtual appliance 10.1.1.4 and 172.16.1.0/24 -> Internet. A VM in the subnet sends traffic to 172.16.1.20. Which next hop is used?

medium

A.Virtual appliance 10.1.1.4, because the broader route was added first.
✓ B.Internet, because the most specific route prefix always wins.
C.Virtual network gateway, because all traffic to private IP addresses uses the gateway by default.
D.No next hop, because conflicting user-defined routes disable routing for that destination.

Why B: Azure route selection uses the longest prefix match (most specific route) to determine the next hop. The route 172.16.1.0/24 is more specific than 172.16.0.0/16, so traffic to 172.16.1.20 uses the Internet next hop, not the virtual appliance. This is consistent with how Azure evaluates user-defined routes (UDRs) and system routes.

Keep practising

Question Discussion

Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.

Loading comments…

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.