What steps are required to change Forms Authentication over to Windows Authentication in an MVC3 web application? - asp.net-mvc-3

Question

I am working on a legacy MVC3 application which uses Forms authentication and SQLMembership Provider for authorizing user access. It has the folowing configuration:
<authentication mode="Forms">
<forms loginUrl="~/Account/Login" timeout="2880" />
</authentication>
<membership>
<providers>
<clear />
<add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices" enablePasswordRetrieval="true" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="true" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="3" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/TimeSheets" passwordFormat="Clear" />
</providers>
</membership>
<profile inherits="Timesheets.Services.UserProfile">
<providers>
<clear />
<add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/TimeSheets" />
</providers>
</profile>
<roleManager enabled="true">
<providers>
<clear />
<add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/TimeSheets" />
<add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/TimeSheets" />
</providers>
</roleManager>
If I create a new MVC application using Windows Authentication this configuration seems to be replaced with configuration like this:
<authentication mode="Windows" />
<authorization>
<deny users="?" />
</authorization>
I have tried just changing the configuration of the legacy MVC site to use this new authentication mode, but this fails to authenticate (I get an Error message "401.2.: Unauthorized: Logon failed due to server configuration.")
However the new web project runs and authenticates correctly (so it's not an AD or local permissions issue)
I had thought to try just putting all the legacy code into the new project but it is rather large and complex and getting everything lined up again in the new site could be very time consuming.
I'm hoping that changing the Auth model should be simpler and less intrusive - But what additional steps would I need to perform to configure the legacy site for Windows Authentication?

Answer 1

The missing part of my configuration change was in the .proj file. This is due to using the IIS Express within Visual Studio.
In order to get the Windows Auth to work in the IIS Express for debugging you need to configure it in the project settings:
The lines:
<IISExpressAnonymousAuthentication />
<IISExpressWindowsAuthentication />
Need to be replaced with:
<IISExpressAnonymousAuthentication>disabled</IISExpressAnonymousAuthentication>
<IISExpressWindowsAuthentication>enabled</IISExpressWindowsAuthentication>