There's a pinned post at the top of the forum on setting up Authentication. If you uncomment the authentication line and put it in the Intratnet or Trusted sites of your Internet Options (this can be done to domain computers using group policy) they should be logged in automatically. The only thing I had to do differently than the instructions on our intranet is I had to uncomment <identity impersonate="true"/> and ad userName="domain\username" and password="password" to the line. Any user account will work as long as it can read the AD (which most can). I used a user with very minimal rights on the domain.

As for where you fixed it....I'm not 100% sure that'll work. I can't remember the line number but you only needed to change it in DNNMembershipModule.vb. That's where the code is currently failing.

This is still an issue with 4.6.2.  The changes I made are listed bellow to work around it.   Just a recap of why these changes are needed:

• When a user is created through AD, the password is not valid, so a call to GetUser which relies on username and password will fail.
• Because it fails, the system will try to create a user, however the username already exists which creates an issue.  In my case, it goes into an endless loop of authentication and rejection.
• I have not tested this against a mixed login environment.  Mine is purely AD based with no forms login.

A current issue with the authentication provider method is that when you get down to the level of CreateUser in the AspNetMembershipProvider, you have no idea which provider sent you there.  I think all of them need to include a DotNetNuke.Services.Authentication.AuthenticationController.SetAuthenticationType call.

DotNetNuke.Authentication.ActiveDirectory.UserController
Public Function AddDNNUser(ByVal AuthenticationUser As UserInfo) As UserCreateStatus
    Dim _portalSettings As PortalSettings = PortalController.GetCurrentPortalSettings
    Dim objSecurity As New PortalSecurity
    DotNetNuke.Services.Authentication.AuthenticationController.SetAuthenticationType("ActiveDirectory")
   
    <snip>

DotNetNuke.Security.Membership.AspNetMembershipProvider

Public Overrides Function CreateUser(ByRef user As UserInfo) As UserCreateStatus
    Dim createStatus As UserCreateStatus
    Dim authType As DotNetNuke.Services.Authentication.AuthenticationInfo = DotNetNuke.Services.Authentication.AuthenticationController.GetAuthenticationType()
    Dim isADSIProvider As Boolean = False
    Dim ProviderTypeName As String = String.Empty
    If Not authType Is Nothing Then ProviderTypeName = authType.AuthenticationType
    isADSIProvider = (ProviderTypeName.IndexOf("ActiveDirectory") >= 0) Or (ProviderTypeName.IndexOf("Authentication.ADSIProvider") >= 0)

    Try
        ' check if username exists in database for any portal
        Dim objVerifyUser As UserInfo = GetUserByUserName(Null.NullInteger, user.Username, False)
        If Not objVerifyUser Is Nothing Then
            If objVerifyUser.IsSuperUser Then
                ' the username belongs to an existing super user
                createStatus = UserCreateStatus.UserAlreadyRegistered
            Else
                ' the username exists so we should now verify the password
                If isADSIProvider Or ValidateUser(objVerifyUser.PortalID, user.Username, user.Membership.Password) Then

                <snip>

Not at this time and I missed John's post above on a possible fix so it missed going into the version I submitted to the release tracker yesterday.

John, could you submit your changes to Gemini if you haven't already.