Just for the case you will login to a newly deployed nice Windows Server 2008 (R2) where Visual Studio 2008 SP1 along with .NET 3.5 SP1 are installed, and you will be tempted (for some reason or other) to start the .NET Framework 2.0 Configuration utility (also known as mscorcfg.msc). You will perhaps search for it and wonder where it has gone? No such utility will be available by default. The mscorcfg.msc is really not there at all. The good news however is, that it could be manually added downloading and installing the latest .NET Framework 2.0 SDK.
There are however reasonable arguments MS has deliberately “forgotten” to update and package this utility into the .NET 3.5 related toolset. The future of CAS is somewhat unfortunate. In other words, in the new .NET Framework 4.0 security was completely redesigned and changed. CLR is moving away from providing security policy for computers. As replacement for CAS policy operating system-level solutions such as Windows Software Restriction Policies (SRP) should apply.
We have seen signs heading in that particular directions learning, that even in .NET 3.5 SP1 CAS was relaxed, meaning that managed applications run from a network share receive a grant set of FullTrust by default. Here some useful links reading about these topics in more detail:
.NET 3.5 SP1 CAS changes:
.NET 4.0 CAS Changes