We are running IIS 6.0 on Windows Server 6.0. And use Windows Media Player (WMP) 11 as client.
We have set up a DRM License Provider Service (license server) that issues DRM licenses upon requests from WMP (a .NET web-app). WMP requests a license from the this server when it tries to play our DRM protected media content.
Before issuing a license, we wish to authenticate the client using an SSL client certificate. So we create a CA-certificate which we install on the server. Then we install a client certificate signed by this CA on the client. Using Internet Explorer (IE) 6 or 7 we can access our web with no problem. The Client Authentication dialog box pops up, we select our client certificate, and get access to resources on the license server.
When WMP pops up a browser window to acquire a DRM license however, the SSL process seems to fail. We only get a page announcing: "HTTP Error 403.7 - Forbidden: SSL client certificate is required." The Client Authentication dialog box never pops up. This is tested with WMP 11.
I have tried the remedies suggested in http://support.microsoft.com/kb/332077
, with no luck.