We have a SharePoint Server 2010 installed internally and another ASP.NET web application using Windows Authentication (same domain and same set of users as SharePoint). We want to configure ASP.NET web application as an external federated search source on SharePoint, it is running fine with Anonymous authentication for configured Federated Locations (using OpenSearch 1.0/1.1 protocol).
However, we would like to configure SharePoint to pass through or authenticate the ASP.NET web application using the same user account logged on SharePoint Sites. But we haven't found any way to do it yet.
Is that possible? And how to achieve that?