Login failed for user '(null)'. Reason: Not associated with a trusted SQL Server connection

Discussion in 'Server Security' started by Peter Afonin, Jun 18, 2004.

  1. Peter Afonin

    Peter Afonin Guest


    Some time ago I posted a message here about my problem: after upgrading the
    domain controller to Windows Server 2003, I couldn't use the SQL server
    trusted connection due to the error: Login failed for user '(null)'. Reason:
    Not associated with a trusted SQL Server connection.

    To solve this problem, I had to open a case with Microsoft. Since recently
    I've received several emails from people with the same problem, I realized
    that I was not alone with this issue, so I decided to post the solution

    There are two ways to fix this problem: to remove TCP/IP protocol from SQL
    server or to impersonate users.

    Remove TCP/IP

    1. Go to SQL Server properties, then to General tab - Network configuration.
    Remove TCP/IP protocol there.

    This worked for me. However, since TCP/IP is required for replication, I had
    to add it back.

    Impersonate SQL Server users.

    Usually you can impersonate users by going to the Local security policy in
    Administrative Tools, then to Impersonate a client after authentication.
    However, if you deal with the Domain controller, most of the controls there
    are disabled. So:

    1. Go to the Active Directory, right-click on Domain Controllers and select
    2. Go to the Group Policy tab and highlight Default Domain Controller
    Policy, click Edit
    3. Go to Windows Settings - Security Settings - Local Policies - User Rights
    4. Double-click Impersonate a client after authentication

    Then Microsoft suggested to uncheck the box Define these policy settings,
    then go to the Local security policy and add users there. It worked.
    However, I think it would be better just add the users right there, without
    going to the Local security policy.

    Either way, this solved my problem.

    Hope this helps.
    Peter Afonin, Jun 18, 2004
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