We have an ASP.NET web application which uses integrated windows authentication. It is accessed by users from two domains, A and B. A is the primary domain and B is an older domain which is going away. Web application is authenticating users using a group policy which only exists in domain A. Every user in domain B has an account in domain A. The application lives in domain A. There was no trust between the domains. So users from domain A would get silently authenticated and logged into the site. Users from domain B didn't get authenticated automatically and were prompted with the IE popup, to which they authenticated using their domain A credentials and everything worked. Now somebody has set up a trust between the domains and users from domain B get authenticated silently to IIS, and then their login fails (no group policy). So the question is: can I either programmatically or in IIS configuration make it so that users from domain B still get prompted even though there is trust between the domains? Is there a way to tell the server where IIS is running to ignore the trust relationship maybe?