SQL SERVER – What is Instance Hiding? How to do it?

SQL SERVER - What is Instance Hiding? How to do it? instance-800x450 In this blog post, I’ll share a real-life success story of how instance hiding significantly strengthened SQL Server security for one of my clients. By leveraging this powerful technique, we successfully protected sensitive data from unauthorized access and created a safer environment for their critical databases.

During my recent engagement with the client, I discovered several SQL Server instances containing valuable customer and financial data. Understandably, my client was concerned about the security risk associated with these exposed instances. They feared that anyone with access to their network could easily find and exploit this sensitive information. Here is my popular service Comprehensive Database Performance Health Check.

Implementing Instance Hiding

To address these concerns, I recommended the implementation of “instance hiding,” a straightforward and effective solution to limit access to the exposed instances. By enabling this feature, new logins could no longer detect or see the instances, granting better control over database accessibility.

Implementing instance hiding was a simple and straightforward process:

  • Accessing SQL Server Configuration Manager: We started by opening the SQL Server Configuration Manager on the client’s main database server.
  • Navigating to SQL Server Network Configuration: Within the Configuration Manager, we found the “SQL Server Network Configuration” section and selected “Protocols for [InstanceToHide].”
  • Enabling Instance Hiding: Next, we right-clicked and selected “Properties” and then went to the “Flags” tab. All we had to do was check the “Hide Instance” box and click “OK” to apply the changes instantly.

How to Connect Post Instance Hiding?

To ensure seamless connectivity to the hidden instances, I updated the client’s connection strings to include the port number associated with the hidden instances. Additionally, I created aliases on each node for high-availability clusters and availability groups, ensuring uninterrupted connectivity during failover.


The results of implementing instance hiding were remarkable. By making sensitive data invisible to unauthorized users, we significantly reduced the risk of potential data breaches and unauthorized access. The success of this approach lies in its simplicity and ability to fortify security while maintaining the smooth functioning of essential database operations.

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Reference: Pinal Dave (https://blog.sqlauthority.com)

SQL Server Configuration, SQL Server Security
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