Login failed for user \.

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Login failed for user \.

srankin

Say Hey Kid

Points: 703
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January 29, 2004 at 9:13 am

#160734

I am trying to execute the following SQL Statement from MyServer...
---------------------------------------------------------------------------
DECLARE @Name
SET @Name = SUSER_SNAME()
--The @Name = 'Domain1\MyUserID'
EXEC sp_AddLinkedServer 'YourServer', 'SQL Server'
EXEC sp_addlinkedsrvlogin @rmtservername = 'YourServer', @userself = 'TRUE'
SELECT * FROM YourServer.YourDB.DBO.YourTable
EXEC sp_droplinkedsrvlogin @rmtservername = 'YourServer', locallogin = @Name
---------------------------------------------------------------------------
I am added as a user on YourServer and YourDatabase
On the Select Statement an Error Occurs
Server: Msg 18456, Level 14, State 1, Line 1
Login failed for user '\'.
Does anyone know how to solve this. It seems obvious that it has something to do with the Domain delimiter of my username.

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vambati SSCrazy Points: 2769 More actions · Answer 1

vambati

SSCrazy

Points: 2769

January 29, 2004 at 10:11 am

#492199

use SET QUOTED_IDENTIFIERS ON/OFF and try.

K. Brian Kelley SSC Guru Points: 114642 More actions · Answer 2

Are you executing the query from Query Analyzer from say a client machine?

K. Brian Kelley
@kbriankelley

Allen Cui-55137 SSC Guru Points: 51650 More actions · Answer 3

Allen Cui-55137

SSC Guru

Points: 51650

January 29, 2004 at 11:13 am

#492221

Are both servers in same domain?

SQLBill SSC Guru Points: 51440 More actions · Answer 4

Is this a typo?

DECLARE @Name

Or did you actually declare @Name as some datatype (ie. VARCHAR(20))?

-SQLBill

srankin Say Hey Kid Points: 703 More actions · Answer 5

It is being executed from a client machine

It is a type-o

and I'll try the QUOTED_IDENTIFIERS

Thanks

K. Brian Kelley SSC Guru Points: 114642 More actions · Answer 6

If it's being executed from a client machine and both the connection from the client machine to the first SQL Server and the connection from the first SQL Server to the second SQL Server are using Windows authentication, you have a potential "double hop" issue. Is this the case? Windows auth on both connections?

K. Brian Kelley
@kbriankelley

srankin Say Hey Kid Points: 703 More actions · Answer 7

I am connected to MyServer via SQL Query Analyzer and Windows Authentication. I am not connected to YourServer except via a Linked Server from within MyServer. As stated above I used @UseSelf = 'TRUE'. Does this try to used Windows Authentication? How does this result in the error 'Login failed for user \.'?

K. Brian Kelley SSC Guru Points: 114642 More actions · Answer 8

Yes, if @UseSelf = 'TRUE' and you're connecting to the SQL Server with Windows authentication, it will attempt to make the connection to the linked server using the same credentials, meaning Windows authentication. This is a double-hop issue.

NTLM, the authentication mechanism under NT 4.0 domains, prohibits re-using the credentials in this manner. Active Directory allows for this using what is known as delegation. However, the account in question has to be set up for delegation and the SQL Server you connect to has to be set up to delegate as well. This occurs within the Active Directory administration side.

Failing that, you'll have to connect on one of the hops with Windows authentication. The article I wrote on Query Analyzer (Part I) goes into this in a bit of detail. There are also some MS Knowledge Base articles on it.

K. Brian Kelley
@kbriankelley