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Login failed for user , Msg 18456, Level 14, State 1
This post focus on a typical cause of sql login failure issue described as the title. In real world, a customer log on to the machine as a domain\user or local machine accout, he can connec to SQL...
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TCP Provider: No connection could be made because the target machine actively...
In this post, I am trying to list out potential cause and general solution to this specific error when you are making connection to SQL Server 2005. First, It is due to TCP connection fail, since you...
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Service Principal Name (SPN)
Did you know that beginning with SQL Server 2008, support for service principal names (SPNs) has been extended to enable mutual authentication across all protocols. Administators can now define their...
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Why Browser is installed under 90\shared directory rathar than 100\Shared?
After installing SQL Server 2008, some users might notice that sqlbrowser.exe is installed under %ProgramFiles%Microsoft SQL Server\90\Shared, rather than %ProgramFiles%Microsoft SQL Server\100\Shared...
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Understanding “Connection forcibly closed by remote host” Errors Caused by...
Sporadic “Connection forcibly closed by remote host” errors with SQL Server connections can be very difficult to troubleshoot and resolve. This blog post is targeted at diagnosing TOE/Chimney issues...
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Could not connect to X64 named instance
We see a couple of cases where customer could not connect to named instance on X64. They all have the following symptons. 1) Customer has no problem to connect X86 instance on the same server machine...
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Steps to troubleshoot SQL connectivity issues
We have been seeing and trying to resolve SQL connectivity issue all the time. I guess it would be helpful if we can put some guidance on how to resolve connectivity issues. Here comes a proposal based...
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Understanding the error message: “Login failed for user ''. The user is not...
Understanding the error message: “Login failed for user ''. The user is not associated with a trusted SQL Server connection.” This exact Login Failed error, with the empty string for the user name, has...
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Connectivity troubleshooting in SQL Server 2008 with the Connectivity Ring...
SQL Server 2008 contains a new feature designed to help troubleshoot particularly tricky connectivity problems. This new feature, the Connectivity Ring Buffer, captures a record for each...
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Troubleshooting SQL Server Cluster Installations
On a Windows Cluster it is possible to install a SQL Server Cluster, which will be a separate entity with disctinct Virtual Server Name, IP address, and pipe name. The nodes of the SQL Cluster must be...
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Connection failure because of mismatched TDS version
Some customers have reported connection failure because of wrong TDS version. The client application gets the following error message: (or similar depends on the protocol used) A connection was...
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Configuring SQL Protocols through Windows PowerShell
Sometimes we are asked about the possibility of configuring SQL Server protocols through PowerShell. In SQL Server 2008, the sqlps tool incorporates WMI and SMO into this powerful...
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Understanding “Data Source=(local)” in SQL Server Connection Strings
Lately we have noticed many misunderstandings surrounding the usage of the Data Source keyword in connection strings, caused by people generalizing from an example demonstrating a connection string for...
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TCP listening ports and ENDPOINT ports behavior
Endpoint configuration seems to be creating some confusion. I hope that this will clarify some of the behavior as it applies to TCP endpoints. With a default configuration of SQL Server, try the...
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Understanding the error “An operation on a socket could not be performed...
This error message, which is associated with the Winsock error WSAENOBUFS and actually comes from Windows rather than SQL Server directly, has two well-understood root causes. However, it still stumps...
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Connection from a Windows Service could be blocked by firewall even if...
Recently, I worked on a customer issue. The customer encountered an "error: 26 - Error Locating Server/Instance Specified" error although he has applied/verified every steps I posted in the...
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We would like to hear your opinion...
Dear SQL Server developers and users: It is this time of the year when we, in the SQL Connectivity product team, take a step back, review the priorities and goals for the long term and identify areas...
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Selectively using secure connection to SQL Server
Secure connection to SQL Server can be enforced by different ways, e.g. forcing encryption by using “ForceEncryption” property under the Network Configuration in the server. But this setting will force...
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SQL Server Native Client survey
Dear SQL Server developers and users: Our sister team, the SQL Server Native Client (SNAC), has a survey open to ask for your feedback as they take a step back to review the priorities and goals for...
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SQL Server "Login Failure" troubleshooter
Our colleagues over in the SQL Server Security team have developed an open tool for troubleshooting "Login Failure" errors. If you're having an issue with "Login Failure" errors and can't resolve it...
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Windows 7 AppCompat changes and SQL Server client and setup hangs
Windows 7 and Windows Server 2008 R2 include many changes to the core operating system. This blog post is targeted at resolving the impact on SQL Server client drivers and SQL Server setup of one...
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SQL Server Customer Survey (Fall 2010)
Greetings to the SQL Server community: Last year in October 2009, we introduced the process of interacting on a regular basis with the developers and users in the form of surveys. During the last...
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Last Chance: Help Shape The Future Of SQL Server!
Hello reader, We have extended our SQL Connectivity Customer Survey until November 2, 2010 5:00PM PST. If you have not done so please take a moment to fill our our easy 10 question survey listed below...
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Annual SQL Connectivity Customer Survey
Greetings to the Developer community: Microsoft SQL Server team has been interacting on a regular basis with the developers and users in the form of surveys. During the last 2 years, we completed...
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Announcing Microsoft SQL Server ODBC Driver for Linux
Greetings Developer community: We heard yesterday and today at the PASS conference about the exciting new areas that we are investing in bringing the power of SQL Server to our customers. Many of our...
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