Use an administrative account to log on to the Web server.
Start IIS Manager or open the IIS snap-in.
Expand Server_name, where Server_name is the name of the server, and then expand Web Sites.
Use one of the following methods (as appropriate to your situation), and then click Properties:
To configure authentication for all Web content that is hosted on the IIS server, right-click Web Sites.
To configure authentication for an individual Web site, right-click the Web site that you want.
To
configure authentication for a virtual directory or a physical
directory in a Web site, click the Web site that you want, and then
right-click the directory that you want, such as _vti_pvt.
To
configure authentication for an individual page or file in a Web site,
click the Web site that you want, click the folder that contains the
file or the page that you want, and then right-click the file or the
page that you want.
In the ItemNameProperties dialog box (where ItemName is the name of the item that you selected), click the Directory Security or the File Security tab (as appropriate).