remote admin connections Option
SQL Server provides a dedicated administrator connection (DAC). The DAC lets an administrator access a running server 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 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 is not 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.
Indicates only local connections are allowed by using the DAC.
Indicates remote connections are allowed by using the DAC.
The following example enables the DAC from a remote computer.
sp_configure 'remote admin connections', 1; GO RECONFIGURE; GO