<configuration>
   <system.web>

      <authentication mode="Windows" />

      <roleManager defaultProvider="WindowsProvider" 
       enabled="true"
       cacheRolesInCookie="false">
         <providers>
            <add
             name="WindowsProvider"
             type="System.Web.Security.WindowsTokenRoleProvider" />
         </providers>
      </roleManager>

   </system.web>
</configuration>
