I have some developer colleagues in my office that are having a problem similar to this one:

db connection uses an anonymous logon instead of the domain user

the connection string (he is working on his local machine) is:

Data Source=localhost\Development;Integrated Security=SSPI;Database=COLA;Connection Reset=FALSE

and it is getting the error message below:

Login failed for user 'NT AUTHORITY\IUSR'.


where this login AUTHORITY\IUSR came from - we don't need it?

How can we make the Integrated Security=SSPI; get his local login instead of the AUTHORITY\IUSR?


2 Answers 2


Following the links in the comments provided by Biju jose and vonPryz

Understanding Built-In User and Group Accounts in IIS 7

Configure ASP.NET Impersonation Authentication (IIS 7)

we were following these steps:

To grant an anonymous account rights on the network by using IIS Manager:

Click Start, type INetMgr.exe, and then click Enter. If prompted, click Continue to elevate your permissions.

  1. In the Connections section, click the + button next to the name of your computer.

  2. In IIS Manager, double-click the site that you want to administer.

  3. In the Features View, double-click Authentication.

  4. Select Anonymous Authentication, and then click Edit in the Actions pane.

  5. In the Edit Anonymous Authentication Credentials dialog box, click the Specific user option, and then click Set.

  6. In the Set Credentials dialog box, input the user name and password desired, and then click OK.

  7. But instead of doing the number 6 we just changed the setting to Application Pool Identity as you can see on the second picture below.

enter image description here

Changing the IIS settings to Application Pool Identity allowed the Windows Authentication to kick in and the active directory account was used to login into sql server.

That account had been previously configured to do so, therefore no more login problems for that user.

enter image description here

I would add that: Is “NT AUTHORITY\ANONYMOUS LOGON” login “mandatory”?


I just got this error and solved it on my own. In SQL Server Management Studio, create a new login NT AUTHORITY\IUSR. Add it to the roles public and systemadmin.

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