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Applies to: 
SQL Server
SQL Server provides a dedicated administrator connection (DAC). You can use the DAC to execute diagnostic functions or Transact-SQL statements, or to troubleshoot problems on the server, even when the server is locked or running in an abnormal state and not responding to a SQL Server Database Engine connection.
By default, the DAC is only available from a client application directly on the server. To enable client applications on remote computers to use the DAC, use the remote admin connections option of sp_configure.
By default, the DAC only listens on the loop-back IP address (127.0.0.1), port 1434. If TCP port 1434 isn't available, a TCP port is dynamically assigned when the Database Engine starts up. When more than one instance of SQL Server is installed on a computer, check the error log for the TCP port number.
The following table lists the possible values for the remote admin connections option.
| Value | Description |
|---|---|
| 0 | Only local connections are allowed by using the DAC. |
| 1 | Remote connections are allowed by using the DAC. |
The following example enables the DAC from a remote computer:
EXEC sp_configure 'remote admin connections', 1;
GO
RECONFIGURE;
GO
Training
Module
Employ remote management - Training
This module demonstrates the various tools for connecting remotely to a Windows client.
Certification
Microsoft Certified: Azure Database Administrator Associate - Certifications
Administer an SQL Server database infrastructure for cloud, on-premises and hybrid relational databases using the Microsoft PaaS relational database offerings.
Documentation
Hide an Instance of SQL Server Database Engine - SQL Server
Find out how to hide an instance of the SQL Server Database Engine. Client computers can't use the SQL Server Browser service to locate hidden instances.
Server Configuration Options - SQL Server, Azure SQL Managed Instance
Find out how to manage and optimize SQL Server and Azure SQL Managed Instance resources. View available configuration options, possible settings, default values, and restart requirements.
Diagnostic Connection for Database Administrators - SQL Server
Find out about the dedicated administrator connection (DAC). View its restrictions, instructions on how to establish it, and examples demonstrating its use.