ADO.NET Cookbook

1.8. Connecting to SQL Server Using Integrated Security from ASP.NET

Problem

You want to coordinate Windows security accounts between an ASP.NET application and SQL Server.

Solution

Connect to SQL Server from ASP.NET using Windows Authentication in SQL Server.

Discussion

Connecting to a SQL Server database provides two different authentication modes:

Windows Authentication

Uses the current security identity from the Windows NT or Windows 2000 user account to provide authentication information. It does not expose the user ID and password and is the recommended method for authenticating a connection.

SQL Server Authentication

Uses a SQL Server login account providing a user ID and password.

Integrated security requires that the SQL Server is running on the same computer as IIS and that all application users are on the same domain so that their credentials are available to IIS. The following areas of the application need to be configured:

• Configure the ASP.NET application so that Integrated Windows Authentication is enabled and Anonymous Access is disabled.

• The web.config file establishes the authentication mode that the application uses and that the application will run as or impersonate the user. Add the following elements to the web.config file:

  <authentication mode="Windows" />
  <identity impersonate="true" />

• The connection string must contain attributes that tell the SQL Server that integrated security is used. Use the Integrated Security=SSPI attribute-and-value pair instead of the User ...