Dedicated Administrator Connection [DAC] in SQL Server

Introduction

DAC [Dedicated Administrator Connection ] is feature added from SQL Server 2005 version . Database administrator use this fetaure to connect to a SQL Server instance When the database engine not responding to the regular connection so the database administrator use this fetaure to connect to the instance to solve the problem Instead of rebooting  the SQL Server.

By Defult this feature is disable in All SQL Server version From 2005 to the New version 2012.

Note :  your SQL Server browser must be Runing

enable the DAC using below T-SQL command

Use master

GO

sp_configure ‘show advanced options’ , 1

GO

sp_configure ‘remote admin connections’, 1

G O RECONFIGURE

GO

enable the DAC using SSMS

1- write click on your SQL Server Probirties >> Factes >>  Service Area Configuration >> RemoteDacEnabled

Change it from False To True

Now try to connect by write ADMN: before your instance name like this

ADMIN:Mostafa-PC\SQLSERVER2008

then your User name and your password or connect windows Authentication but if you try to connect by the default way SQL Server will give you this Error

Dedicated administrator connections are not supported. (ObjectExplorer)

 

So if you want to connect with this Feature you must make this steps

Go to File >>> New >>> Database Engine Query >>>> Admin:InstanceName

 then your Session will open

Note : You can not open 2 Session