I am somehow confused whether I need the Middle Tier Server.

We want to use Win 2K3 Server, edir 873 and ZfD7 SP1 IR4, Clients not NW
Client. Do we need the Mid Tier, if the Apps are stored on the Win Server?

There is now access from the Internet needed, alle we need to have is the
domain login and the eDir Login for some ZEN Apps.

I have gone through some docs, but somehow I am confusesd a bit..