Configuring Windows Authentication

 Windows authentication is enabled by default in the Machine. Config file. This setting is automatically inherited by all ASP.NET applications running on the same server.

If you have modified the Machine.Config file-for example, you have set the default authen­tication method to Forms authentication-you can explicitly enable Windows authentica­tion for an application by adding the Web. Config file in Listing 20.1 to the application root directory.

You cannot add the file in abobe example to any directory beneath an application's root directory.In other words, it must be located in either the wwwroot directory or the root of a virtual directory.

Configuring Windows Authentication

After the Windows authentication is enabled, authorization can be provided to particular users ­and groups to access particular directories and files by using Web.Config file.

A Web. Config file can be added that includes an authorization section to any (not only the application root directory). Within the authorization section, the users and groups can be listed who have access to files in that directory.

The authorization section can contain two elements: deny and allow. These elements can be used to allow or deny a list of Windows users or groups access to the files in the current directory. For example, the Web. Config file in example 68 explicitly allows access to anyone in the Sales group, except for Sam.

 The authorization section uses a "first match" algorithm to allow or deny users and groups ­accessed to a page. Since the Sales role is allowed, access before everyone is denied. Anyone in the Sales role is given authorization to access any page in the directory.

Notice that the domain must be specified when listing user accounts and groups. If the user account or group is a local machine account, the domain is the name of your server.

Two special wildcard characters can be used in the authorization section of the Web. Config file. The * wildcard character represents all users, and the ? represents all unauthenticated users. For example, if you want to force all users to login ­before accessing a file in a directory, you can use the Web. Config file in Example 69 below: -

ay that you need to create two directories named Managers and Sales. You want to enable only users in the Managers group to access the files in the Managers directory. However, you want to enable members of the Managers and Sales groups to access all the files in the Sales directory.

The files are listed below: -

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