<p>I would like to set up some WMV Video Streaming, using Windows 2003's Streaming Media Server and Silverlight.</p>

<p>Now, unfortunately Silverlight only supports HTTP, which means that people can just download the videos. While that in itself is not a problem, I wonder what options there are to prevent them being playable outside of the network.</p>

<p>Of course, DRM comes into mind. Is there an easy way to get it and set it up? I do not want to have some complicated User-Scheme, it essentially boils down to "If you can reach the server (which is only in the internal network), you get a license, otherwise not".</p>

<p>Any experience with WMV DRM or Content Protection in that area?
What would I need on top of Windows 2003 Server and Silverlight 2?</p>

DRM is a negative sum game.  You lose money and time in implementing it that you could have spent on something useful to your users, and your content becomes less valuable to your users.  It is also impossible to implement effectively.  I'm not going to address any specific DRM scheme, but the core of the argument is that in order to show content to the user, the user's computer must be able to decrypt it.  Therefore, the decryption code, and the decryption keys, must be present on the user's computer.  Encryption can only protect data from interception and tampering between two secure endpoints.  If one of the endpoints is compromised (and you are assuming this in your distrust of the user), then cryptographic techniques are useless.