Just to be clear, by authentication I don't mean user-authentication, but I want to make sure that my app is running on the customer's server and in a defined time-span.
Some of our customers use our web apps in their Intranet and on their own servers, on the other hand some of them use Hosting services and they don't own any server machine.
With that said, I'm looking for ways to make sure about customer's Identity. I don't want them to be able to xcopy the app, also I'd like to have some kind of time-expiration limit.
In traditional desktop apps we could use USB security tokens, but their not usable with hosting providers.
It seems that we have to make a central authentication server. I'm a little confused about possible options, so any suggestion about where to start is welcome.