.net 3.5 iis : 2 logical questions

I am a little bit confused about 2 things.

Firstly when I create an IIS site, I have the option to have the .net version set to 1 or 2 and their respected sub versions. However the DLL's I've compiled and shipped to the bin are for .net framework v3.5. What is the relationship here between v3.5 and v2, because it seems from an IIS point of view, the highest you can set the version is 2.

Since we're on the subject, can you still use impersonation on a site using 3.5 assemblies? I have impersonation set to an account that is in the local admin group, but I had certificate permission issues, till I changed the app pool to run under local system. I really thought impersonation was the deciding factor with permissions, is impersonation obsolete with 3.5, or is there something I am missing out on, some vital 开发者_如何转开发clue?

Thanks in advance

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.NET 3.5 is just a BCL (Base Class Library) extensions - a set of additional assemblies. .NET 3.5 runs on the same CLR as .NET 2.0.

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As Vitality said, .Net 3.5 is the same CLR as .Net 2.0. The next time this will change is when you install .Net 4.0 as this is a new CLR then you will have options of 1, 2, 4 for versions.