Dedicated Administrator Connection

  • I thought the DAC was accessible by logging on directly from the server but when I try to do this I get an error message:

    HResult 0x274D, Level 16, State 1

    TCP Provider: No connection could be made because the target machine actively refused it.

    Sqlcmd: Error: Microsoft SQL Native Client : An error has occurred while establishing a connection to the server. When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections..

    Sqlcmd: Error: Microsoft SQL Native Client : Login timeout expired.

    I can only get it to work by enabling the "remote admin connections" option. Has anyone else experienced this?

  • What version of SQL Server 2005? Is this a cluster?

    K. Brian Kelley
    @kbriankelley

  • SQL 2005 Standard SP2 x64. Yes, it's part of a cluster but not an MS SQL cluster.

  • Read this ?

    SQL Server 2005 Books Online (September 2007)

    How to: Use the Dedicated Administrator Connection with SQL Server Management Studio

    Microsoft SQL Server 2005 provides a dedicated administrator connection (DAC). The DAC allows an administrator to access a running instance of SQL Server Database Engine to troubleshoot problems on the server—even when the server is unresponsive to other client connections. The DAC is available through the sqlcmd utility and SQL Server Management Studio. The connection is only allowed from a client running on the server. No network connections are permitted.

    To use SQL Server Management Studio with the DAC, connect to an instance of the SQL Server Database Engine with Query Editor by typing ADMIN: before the server name. Object Explorer cannot connect using the DAC.

    To connect to a server using the DAC

    1.

    In SQL Server Management Studio, with no other DACs open, on the toolbar, click Database Engine Query.

    2.

    In the Connect to Database Engine dialog box, in the Server name box, type ADMIN: followed by the name of the server instance. For example, to connect to a server instance named ACCT\PAYABLE, type ADMIN:ACCT\PAYABLE.

    3.

    Complete the Authentication section, providing credentials for a member of the sysadmin group, and then click Connect.

    The connection is made.

    If the DAC is already in use, the connection will fail with an error indicating it cannot connect.

    See Also blah blah blah


    The systems fine with no users loggged in. Can we keep it that way ?br>

  • I read the BOL article. It says that you can connect via a client on the server which is exactly what I'm doing. It only works if I enable the remote admin connections option though, which I do not want to enable.

  • Hi JWOL,

    This can certainly be done as I have implemented such a configuration on a clustered environments.

    As I am sure you know, you cannot use the standard connection prompt in SSMS, you must use File > New > Database Engine Query, from the menu in order to establish the DAC connection.

    Could be a long shot but in order to get the DAC working in a particular cluster configuration I havw worked with, we had to ensure the the MSDTC was configured sepcifically for a clustered environemnt. The following article was used to rectify this

    http://support.microsoft.com/kb/223397/en-us

    Hope this helps.

    John


    John Sansom (@sqlBrit) | www.johnsansom.com

  • Yes, I was trying via the "database engine query" button. I don't have time to try everything in that DTC article at the moment but thanks for the link. For now, I suppose I will have to allow remote connections.

  • Does the name and IP address of the SQL Server differ from the local server name and IP?

    K. Brian Kelley
    @kbriankelley

  • Yes, it does. There are several instances on the same machine all with different IP addresses.

  • Then that's likely why it appears as a remote connection. IPs don't match, etc.

    K. Brian Kelley
    @kbriankelley

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