Thanks for the reply!

I checked the things you described: ASP.NET is running. Windows authentication is enabled and the user i impersonate (myself) has full rights on this folder.

The Problem i am facing at the moment:

1) As long as there is no DNN on the server the windows authentication is working

[asp or aspx File with a simple web.config-File that enables impersonation, set windows as authentication mode and denys the ?-User (annonymous) ]

2) When I have DNN on the Server the asp-Script still gives me the User, but the aspx-Script will open a Window to insert Username and Password. But no matter what  I insert it will not grant me access.

[DNN web.config, switched the part from Forms to Windows authentication, enabled the impersonation and add the deny ?-User

I tried the same Scenarios on a lokal Server and it is behaving the same way.

The only Problem I can think of is, that the DNN web.config contains some parts that does not work well with the Authentication.

I really have no clue how to make it working.

(As the .asp File is working i thought of calling the asp-page from within my dnn-module and read the responsestream for getting the user. The Problem here is that i will actually get the User of the IIS Server, as there is no Imersonation with the Anonymous User.)

 I changed the web.config back to the default values.

Still the homepage will not load if no anonymous authentication is enabled or allowed in the web.config.

I finnaly found a workaround to get it going. I am using a clientside redirect so the user visits my classic asp script located on the server. There I read the LOGON_USER which is set even on anonymous authentication and save it into a cookie. Afterwards there is another clientside redirect back to the homepage. Every Module that needs the userinformation reads it from that cookie or does the redirect to set it first.

So after all it it working somehow now.

Thanks for all your help so far. If you sometime in the future have a clue what could cause the problems i faced, please let me know.