Securing certain apps w/ NTFS?

We are having problems using IIS and ISAPI_reverse proxy to mongrel for
our login page. It appears as thought the cookies aren’t being passed
or certain info doesn’t match.

Is it possible to use NTFS permissions to secure certain portions of the
app? I have tried applied more strict permissions on the app contorller
I am trying to secure, but is doesn’t prompt for credentials.

Is this possible? If not anyone have any insight on why my login page
isn’t working?