DP-300 Implement a secure environment Practice Question
You are the database administrator for a company that uses Azure SQL Database. The company has a strict security policy requiring that all database connections be encrypted using TLS 1.2 or higher and that the server certificate be validated to prevent man-in-the-middle attacks. Additionally, the company wants to ensure that only applications running on Azure virtual machines (VMs) in a specific virtual network (VNet) can access the database. The VMs use a subnet named 'AppSubnet'. You have configured the following: 1. The server 'Allow Azure Services' setting is OFF. 2. A virtual network rule is added for 'AppSubnet' with the service endpoint for Microsoft.Sql enabled. 3. The server firewall has no other rules. 4. The 'Minimum TLS version' is set to 1.2. 5. All client applications are configured to use 'Encrypt=True' and 'TrustServerCertificate=False' in their connection strings.
After deployment, you discover that connections from the VMs are failing with error: 'The certificate chain was issued by an authority that is not trusted'. What is the most likely cause of this issue?
⚠ Common exam trap
Watch out — candidates often confuse a certificate trust error with network connectivity or TLS version issues, assuming the problem is with the firewall or TLS configuration rather than the client's certificate store.
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 VMs do not have the necessary root CA certificates installed to validate the Azure SQL Database server certificate.
The error 'The certificate chain was issued by an authority that is not trusted' indicates that the client cannot validate the Azure SQL Database server certificate. With 'TrustServerCertificate=False', the client must trust the server's certificate chain, which requires the root CA certificates (e.g., Baltimore CyberTrust Root) to be installed in the VM's trusted root store. Since the VMs are in Azure, they typically have these certificates, but custom images or hardened VMs may lack them, causing the validation failure.
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 client applications are using an older version of .NET that does not support TLS 1.2.
Why it's wrong here
Incorrect: TLS 1.2 is supported; the error is about certificate validation.
- ✗
The virtual network rule is missing the service endpoint for Microsoft.Sql on the subnet.
Why it's wrong here
Incorrect: The exhibit states the service endpoint is enabled.
- ✗
The server firewall is blocking traffic from the VNet because 'Allow Azure Services' is OFF.
Why it's wrong here
Incorrect: The VNet rule allows traffic; 'Allow Azure Services' is for other Azure services.
- ✓
The VMs do not have the necessary root CA certificates installed to validate the Azure SQL Database server certificate.
Why this is correct
Correct: The certificate chain validation fails if root CAs are missing.
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Learn chapter
Overview of Azure Data Platform Options
Key term
Azure SQL Performance Tuning
Azure SQL Performance Tuning is the process of optimizing the speed and efficiency of queries and database operations in Microsoft Azure SQL Database or SQL Managed Instance to reduce latency and improve throughput.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DP-300 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 DP-300 exam.