We are looking at implementing CRM 2013 to a small user group of salesman 15-25. As it stands we will have these servers in our internal network. CRM2013 Application server hosting all rules, SQL server, ADFS 2.0 server. We are looking to add ADFS proxy and CRM 2013 IFD services to our perimeter network. The question I'm looking to answer as simple as it sounds is, does the IFD web server need to be joined to the domain?