Private Endpoint DNS Resolution: How to Link a Private DNS Zone
Exhibit
From VM-B in VNet-B: nslookup mystorage.blob.core.windows.net returns 20.52.10.7; the storage account has a private endpoint in VNet-A at 10.4.1.5; the private DNS zone privatelink.blob.core.windows.net is linked only to VNet-A.
Based on the exhibit, what should the administrator do so VM-B resolves the storage account name to the private IP address?
Quick Answer
The answer is to link the private DNS zone to VNet-B. This is correct because private endpoint DNS resolution relies on a linked private DNS zone to override the default public DNS record for the storage account’s fully qualified domain name. When the zone is linked to VNet-B, Azure’s default DNS servers within that virtual network will resolve the storage account name to the private IP address of the endpoint, ensuring traffic stays on the Microsoft backbone. On the AZ-104 exam, this scenario tests your understanding of how private endpoints and DNS zones interact—a common trap is assuming that creating the private endpoint alone is sufficient, when in fact the zone must be explicitly linked to each VNet that needs private resolution. Remember the key rule: a private endpoint creates the private IP, but the DNS zone link enables the name resolution. Memory tip: “Link the zone, or the DNS roams.”
⚠ Common exam trap
Test-takers frequently confuse network-level controls (like service endpoints or route tables) with DNS resolution, assuming that private connectivity alone will automatically change name resolution without explicitly linking the private DNS zone.
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
✓
Link the private DNS zone to VNet-B.
The private DNS zone for the storage account must be linked to VNet-B so that VM-B can resolve the storage account's fully qualified domain name (FQDN) to the private IP address of the private endpoint. Without this link, the DNS resolution will fall back to the public endpoint, bypassing the private connectivity. Linking the zone ensures Azure's default DNS servers return the private IP for the storage account within VNet-B.
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 a service endpoint on VNet-B and leave DNS unchanged.
Why it's wrong here
A service endpoint does not create private DNS resolution for the storage account name.
When this WOULD be correct
This option would be correct if the question asked: 'How can you ensure that traffic from VM-B to the storage account stays within the Azure backbone network without using a private endpoint?' In that scenario, a service endpoint on VNet-B would route traffic to the storage account's public endpoint over the Azure backbone.
- ✓
Link the private DNS zone to VNet-B.
Why this is correct
The DNS zone link lets workloads in VNet-B resolve the storage name to the private endpoint address.
- ✗
Assign a public IP address to the private endpoint.
Why it's wrong here
Private endpoints use private IP addresses, so adding a public IP defeats the design.
When this WOULD be correct
If the question were about enabling internet-based clients to access a storage account through a private endpoint (e.g., for hybrid scenarios), assigning a public IP to the private endpoint could be part of a solution to allow inbound traffic from the internet while still using private IP for internal traffic.
- ✗
Add a route table with a next hop to the storage account.
Why it's wrong here
Routing does not control name resolution, so this does not fix the DNS symptom.
When this WOULD be correct
This option would be correct if the question were about ensuring traffic from VM-B to the storage account goes through a specific network virtual appliance (NVA) or firewall for inspection, and the storage account is accessed via its public endpoint. In that case, a route table with a next hop to the NVA would force traffic accordingly.
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.
✓Link the private DNS zone to VNet-B.Correct answer▾
Why this is correct
The DNS zone link lets workloads in VNet-B resolve the storage name to the private endpoint address.
✗Create a service endpoint on VNet-B and leave DNS unchanged.Wrong answer — click to see why▾
Why this is wrong here
Creating a service endpoint on VNet-B does not enable private DNS resolution for the storage account; it only allows traffic to the storage account's public endpoint via the Azure backbone network. The question requires resolving the storage account name to a private IP address, which requires linking the private DNS zone to VNet-B.
★ When this WOULD be the correct answer
This option would be correct if the question asked: 'How can you ensure that traffic from VM-B to the storage account stays within the Azure backbone network without using a private endpoint?' In that scenario, a service endpoint on VNet-B would route traffic to the storage account's public endpoint over the Azure backbone.
Why candidates choose this
Candidates may confuse service endpoints with private endpoints, thinking both provide private IP resolution. They might also believe that a service endpoint alone can change DNS resolution, which it cannot.
✗Assign a public IP address to the private endpoint.Wrong answer — click to see why▾
Why this is wrong here
Assigning a public IP to the private endpoint does not affect DNS resolution for the storage account; it only exposes the endpoint to the internet, which defeats the purpose of private connectivity and does not make VM-B resolve the name to the private IP.
★ When this WOULD be the correct answer
If the question were about enabling internet-based clients to access a storage account through a private endpoint (e.g., for hybrid scenarios), assigning a public IP to the private endpoint could be part of a solution to allow inbound traffic from the internet while still using private IP for internal traffic.
Why candidates choose this
Candidates may think that adding a public IP to the private endpoint will make the endpoint reachable and thus DNS resolution will work, confusing connectivity with DNS resolution.
✗Add a route table with a next hop to the storage account.Wrong answer — click to see why▾
Why this is wrong here
Adding a route table with a next hop to the storage account does not affect DNS resolution; it only controls network traffic routing. The issue is that VM-B cannot resolve the storage account name to the private IP address, which requires DNS configuration, not routing.
★ When this WOULD be the correct answer
This option would be correct if the question were about ensuring traffic from VM-B to the storage account goes through a specific network virtual appliance (NVA) or firewall for inspection, and the storage account is accessed via its public endpoint. In that case, a route table with a next hop to the NVA would force traffic accordingly.
Why candidates choose this
Candidates may confuse DNS resolution with network routing, thinking that directing traffic to the storage account's IP via a route table will also make the name resolve to that IP. They overlook that DNS is separate from routing.
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?”
Visual reference
Go deeper
Related to this question
Learn chapter
Managed Identities for Azure Resources
Key term
Private IP address
A private IP address is a non-internet-routable address used within a local network to identify devices and allow them to communicate with each other without direct exposure to the public internet.
Key term
Storage account
A cloud storage account is a container that holds a set of cloud storage services and their data, providing a unique namespace and access policies for storing and managing unstructured data.
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Same concept, more angles
7 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. After a private endpoint for an Azure Blob Storage account is created, VMs in the same VNet still resolve the storage name to the public IP address. The administrator wants the name to resolve to the private endpoint address instead. What should be configured?
medium- ✓ A.Link the private DNS zone for blob storage to the virtual network.
- B.Create a route table that sends storage traffic to the private endpoint subnet.
- C.Enable a service endpoint on the subnet that hosts the VMs.
- D.Assign a public IP address to the private endpoint subnet.
Why A: When a private endpoint is created for Azure Blob Storage, the private DNS zone (privatelink.blob.core.windows.net) must be linked to the virtual network to enable automatic resolution of the storage account's FQDN to the private endpoint's private IP address. Without this link, VMs in the VNet continue to use public DNS resolution, which returns the public IP. Linking the private DNS zone to the VNet ensures that DNS queries from VMs resolve to the private endpoint address via Azure's DNS infrastructure.
Variation 2. A storage account already has a private endpoint for Blob service in a VNet. Virtual machines in AppSubnet still resolve the account name to the public endpoint, so traffic never reaches the private IP. Which two actions should the administrator take? Select two.
hard- ✓ A.Create a private DNS zone for privatelink.blob.core.windows.net.
- ✓ B.Link the private DNS zone to the VNet used by AppSubnet.
- C.Enable a service endpoint for Microsoft.Storage on the subnet.
- D.Set the storage account firewall to Selected networks without a private endpoint.
- E.Assign a static public IP to the private endpoint.
Why A: A private DNS zone for `privatelink.blob.core.windows.net` is required to override the default public DNS resolution for the storage account. When a private endpoint is created, the storage account's FQDN (e.g., `mystorageaccount.blob.core.windows.net`) must resolve to the private IP address of the endpoint within the VNet. Without this DNS zone, the VM in AppSubnet will continue to resolve the name to the public IP via Azure's public DNS servers, bypassing the private endpoint.
Variation 3. You create a private endpoint for an Azure Storage account and disable public network access on the account. A VM in a peered VNet cannot reach the storage account by name. The private endpoint resides in VNet-App. What is the most likely missing configuration?
hard- ✓ A.A private DNS zone linked so the relevant VNet can resolve the storage account to the private endpoint IP
- B.An NSG rule allowing outbound DNS to 8.8.8.8
- C.A Recovery Services vault in the peered VNet
- D.A public IP address on the private endpoint NIC
Why A: When you create a private endpoint for an Azure Storage account and disable public network access, the storage account's public DNS name must resolve to the private endpoint's private IP address within the VNet. This requires a private DNS zone (privatelink.blob.core.windows.net) linked to the VNet where the VM resides. Without that DNS zone link, the VM in the peered VNet will resolve the storage account name to the public IP, which is unreachable because public access is disabled, causing the connection failure.
Variation 4. You create a private endpoint for an Azure Storage account. Virtual machines in VNet-Prod must resolve the storage account name to the private IP address of that endpoint. Which Azure feature should you configure?
medium- ✓ A.A private DNS zone linked to VNet-Prod
- B.A user-defined route
- C.An Azure Firewall policy
- D.A Recovery Services vault
Why A: A private endpoint uses a private IP address from the VNet, but DNS resolution must be explicitly configured to map the storage account's FQDN to that private IP. By creating a private DNS zone (privatelink.blob.core.windows.net) linked to VNet-Prod, Azure automatically creates an A record for the private endpoint IP, enabling VMs to resolve the storage account name to the private IP instead of the public IP.
Variation 5. You create a private endpoint for an Azure Storage account. Virtual machines in VNet-App must resolve the storage account name to the private IP address of the endpoint. What should you configure?
medium- ✓ A.A private DNS zone linked to VNet-App
- B.A user-defined route on the subnet
- C.An additional public IP address
- D.An Azure Firewall policy
Why A: A private DNS zone linked to VNet-App is required because Azure Private Endpoint uses a private IP address from the virtual network, but the storage account's fully qualified domain name (FQDN) must resolve to that private IP within the VNet. By linking a private DNS zone (e.g., `privatelink.blob.core.windows.net`) to VNet-App and configuring an A record for the endpoint's private IP, VMs can resolve the storage account name to the correct private address. Without this, DNS resolution would fall back to the public IP, defeating the purpose of the private endpoint.
Variation 6. You deploy a private endpoint for an Azure Storage account. Virtual machines in VNet-App must resolve the storage account name to the private IP address of the endpoint instead of the public endpoint. What should you configure?
medium- A.A network security group on the subnet.
- ✓ B.A private DNS zone linked to VNet-App.
- C.A public DNS zone for the storage account name.
- D.A user-defined route table on the subnet.
Why B: A private endpoint requires DNS resolution to map the storage account's fully qualified domain name (FQDN) to its private IP address. By creating a private DNS zone (privatelink.blob.core.windows.net) and linking it to VNet-App, Azure automatically creates an A-record pointing to the private endpoint's IP, ensuring VMs resolve the storage account name privately instead of via the public endpoint.
Variation 7. A team deployed a private endpoint for an Azure Storage account in VNet-A. The private endpoint is healthy, but VMs in VNet-A still resolve the storage account name to the public IP address. What should the administrator configure next?
medium- A.Add a route table that sends storage traffic to the private endpoint.
- ✓ B.Link the appropriate private DNS zone to VNet-A.
- C.Create a network security group rule that allows outbound HTTPS.
- D.Enable service endpoints for Microsoft.Storage on the subnet.
Why B: When a private endpoint is deployed, the storage account's FQDN must resolve to the private IP address within the virtual network. By default, Azure Private DNS zones (privatelink.blob.core.windows.net) are not automatically linked to the virtual network. Linking the private DNS zone to VNet-A enables DNS resolution of the storage account name to the private endpoint's IP address instead of the public IP.
JA
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.