AZ-104 Implement and Manage Virtual Networking Practice Question
A subnet contains several application servers. You need to allow inbound TCP 3389 only from a management subnet named Subnet-Mgmt and deny RDP from all other sources. What should you do?
⚠ Common exam trap
Candidates often think they need to explicitly create a deny rule for all other sources, not realizing that NSGs have a built-in default deny rule that automatically blocks traffic not matching any allow rule.
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
✓
Create an NSG rule allowing TCP 3389 from the Subnet-Mgmt address range and rely on the default deny afterward.
Network Security Groups (NSGs) in Azure filter traffic based on rules that are evaluated in priority order. By creating an inbound rule that allows TCP 3389 (RDP) from the Subnet-Mgmt address range, and relying on the default implicit deny rule that blocks all other inbound traffic, you effectively restrict RDP access to only the management subnet. No additional configuration is needed to deny traffic from other sources, as the default deny handles that automatically.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Create an NSG rule allowing TCP 3389 from the Subnet-Mgmt address range and rely on the default deny afterward.
Why this is correct
An NSG rule with source 'Subnet-Mgmt', destination 'Any', and destination port 3389 (TCP) will explicitly allow RDP only from that management subnet. Because the default inbound deny rule (priority 65000) blocks all other sources, any connection attempt from outside the prefix is implicitly rejected. This is the standard least-privilege approach for restricting administrative access to VMs, and it works at the network layer without requiring a separate appliance or routing change.
- ✗
Create a route table that sends RDP traffic to the management subnet.
Why it's wrong here
User-defined routes (UDRs) control the next hop of packets based on destination IP address prefixes; they cannot inspect TCP/UDP ports or protocols. A route table that directs RDP traffic to the management subnet would only change the path packets take, not block unauthorized clients from reaching the server. Route tables are a traffic-routing mechanism, not a security control for port-level access, so they cannot replace an NSG rule for permitting a specific source address.
When this WOULD be correct
If the question asked to force RDP traffic from the application subnet to go through a network virtual appliance (NVA) in the management subnet for inspection, then a route table with a route for 3389 traffic to the NVA would be correct.
- ✗
Deploy a private endpoint for each application server.
Why it's wrong here
Private endpoints are network interfaces that connect Azure PaaS services (e.g., Storage, SQL Database) to a virtual network using private IP addresses, essentially bringing those services inside the VNet. They cannot be attached to IaaS VMs, so deploying one for each application server is not even possible, and they do not evaluate source addresses of inbound RDP traffic. Private endpoints exist to enable private connectivity to PaaS endpoints, not to filter administrative access to VMs.
When this WOULD be correct
When you need to securely connect to an Azure PaaS service (e.g., Azure SQL Database, Storage Account) from a virtual network, ensuring traffic never traverses the public internet. The question would specify a PaaS service and require private connectivity.
- ✗
Enable service endpoints on the application subnet.
Why it's wrong here
Service endpoints extend a VNet's identity and private address space to Azure services like Storage or SQL over the Microsoft backbone, and they secure that traffic by preventing public internet access to those PaaS resources. They do not apply to VM-to-VM traffic or RDP management traffic; enabling service endpoints on the application subnet would have no effect on whether TCP 3389 is allowed from a specific source. Service endpoints are a networking feature for Azure service connectivity, not a substitute for NSG rules that control port-based access to VMs.
When this WOULD be correct
When you need to restrict access from a subnet to an Azure PaaS service (e.g., Azure Storage or SQL Database) to only allow traffic from that subnet, you would enable a service endpoint and create a firewall rule on the service.
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.
✓Create an NSG rule allowing TCP 3389 from the Subnet-Mgmt address range and rely on the default deny afterward.Correct answer▾
Why this is correct
An NSG rule with source 'Subnet-Mgmt', destination 'Any', and destination port 3389 (TCP) will explicitly allow RDP only from that management subnet. Because the default inbound deny rule (priority 65000) blocks all other sources, any connection attempt from outside the prefix is implicitly rejected. This is the standard least-privilege approach for restricting administrative access to VMs, and it works at the network layer without requiring a separate appliance or routing change.
✗Create a route table that sends RDP traffic to the management subnet.Wrong answer — click to see why▾
Why this is wrong here
Route tables control traffic routing between subnets, not security filtering. They cannot deny or allow specific ports like RDP (3389); they only determine the next hop for traffic.
★ When this WOULD be the correct answer
If the question asked to force RDP traffic from the application subnet to go through a network virtual appliance (NVA) in the management subnet for inspection, then a route table with a route for 3389 traffic to the NVA would be correct.
Why candidates choose this
Candidates may confuse routing with security filtering, thinking that directing RDP traffic to the management subnet implicitly restricts access, or they may overestimate the capabilities of route tables.
✗Deploy a private endpoint for each application server.Wrong answer — click to see why▾
Why this is wrong here
Private endpoints are used to securely access Azure PaaS services over a private IP address, not to restrict inbound RDP traffic to VMs. They do not filter network traffic like NSGs and cannot deny RDP from specific subnets.
★ When this WOULD be the correct answer
When you need to securely connect to an Azure PaaS service (e.g., Azure SQL Database, Storage Account) from a virtual network, ensuring traffic never traverses the public internet. The question would specify a PaaS service and require private connectivity.
Why candidates choose this
Candidates may confuse private endpoints with network security controls, thinking they can restrict access to VMs, or they may overcomplicate the solution by introducing a feature designed for PaaS services instead of using a simple NSG rule.
✗Enable service endpoints on the application subnet.Wrong answer — click to see why▾
Why this is wrong here
Service endpoints secure Azure service traffic to a virtual network, not inbound RDP access. They do not filter or deny traffic like NSG rules, so they cannot restrict RDP from specific subnets.
★ When this WOULD be the correct answer
When you need to restrict access from a subnet to an Azure PaaS service (e.g., Azure Storage or SQL Database) to only allow traffic from that subnet, you would enable a service endpoint and create a firewall rule on the service.
Why candidates choose this
Candidates may confuse service endpoints with network security controls, thinking they can restrict inbound traffic to VMs, or they may misapply the concept of securing resources to a virtual network.
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?”
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Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
Key term
Network security
Network security is the practice of protecting a computer network from unauthorized access, misuse, malfunction, modification, destruction, or improper disclosure, ensuring the confidentiality, integrity, and availability of data and resources.
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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.