NTLM Authentication Across Forests

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  1. #1

    Default NTLM Authentication Across Forests

    I have a problem that I've spent a considerable amount of time
    researching and still haven't quite found the answer.

    I have an intranet web server in Domain A if Forest A. This server
    contains a website which in turn contains two files TestAccess.html
    and TestAccess.aspx. Both files have security settings which allow
    access to only one user Domain B\UserX. The user belongs to Domain B
    which is part of Forest B. All domains and forests are currently
    Window 2000. I also use .Net Framework 1.1. IIS is set up to use
    integrated authentication and there is a one way external trust
    between Domain A and Domain B (that is Domain A trusts Domain B).

    The problem is as follows. When UserX browses to the website and
    tries to access page TestAccess.html the page is served successfully.
    However, when the same user attempts to view page TestAccess.aspx, he
    gets an access denied error. Why is it so?

    Considering that the domains are in separate forests and that Kerberos
    authentication does not work across forests via external trust, the
    browser uses NTLM authentication. I've read multiple posts on the
    double-hop issue with NTLM, but this does not seem to apply here,
    since both .html and .aspx files reside on the same web server.

    I also tested the same website with a UserY in DomainA and everything
    worked fine, i.e. both pages could be viewed just fine. The security
    logs indicated that in this case Kerberos was used for authentication.

    So my question is: Why is the .aspx page not served to UserX? Do I
    have some kind of double-hop situation here even if the files are on
    the same machine?

    Please, help me make sense of this.
    Andrew Guest

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  3. #2

    Default Re: NTLM Authentication Across Forests

    Are you using impersonation in your web.config?

    Joe K.

    "Andrew" <andrew.miadowicz@gmail.com> wrote in message
    news:d6565709.0411040834.564f95f1@posting.google.c om...
    >I have a problem that I've spent a considerable amount of time
    > researching and still haven't quite found the answer.
    >
    > I have an intranet web server in Domain A if Forest A. This server
    > contains a website which in turn contains two files TestAccess.html
    > and TestAccess.aspx. Both files have security settings which allow
    > access to only one user Domain B\UserX. The user belongs to Domain B
    > which is part of Forest B. All domains and forests are currently
    > Window 2000. I also use .Net Framework 1.1. IIS is set up to use
    > integrated authentication and there is a one way external trust
    > between Domain A and Domain B (that is Domain A trusts Domain B).
    >
    > The problem is as follows. When UserX browses to the website and
    > tries to access page TestAccess.html the page is served successfully.
    > However, when the same user attempts to view page TestAccess.aspx, he
    > gets an access denied error. Why is it so?
    >
    > Considering that the domains are in separate forests and that Kerberos
    > authentication does not work across forests via external trust, the
    > browser uses NTLM authentication. I've read multiple posts on the
    > double-hop issue with NTLM, but this does not seem to apply here,
    > since both .html and .aspx files reside on the same web server.
    >
    > I also tested the same website with a UserY in DomainA and everything
    > worked fine, i.e. both pages could be viewed just fine. The security
    > logs indicated that in this case Kerberos was used for authentication.
    >
    > So my question is: Why is the .aspx page not served to UserX? Do I
    > have some kind of double-hop situation here even if the files are on
    > the same machine?
    >
    > Please, help me make sense of this.

    Joe Kaplan \(MVP - ADSI\) Guest

  4. #3

    Default Re: NTLM Authentication Across Forests

    Yes, I have asp worker process set up to impersonate. Also, the
    worker process runs as a "Domain A\AccountS".
    Andrew Guest

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