You can use Powershell to show the available Windows Features:
Import-Module ServerManager
Get-WindowsFeature | out-file C:\WindowsFeatures.txt -width 300
Because the data is a long and wide it is better to pipe it into a file and review it there.
it shows that '.NET Framework 3.5 Features' are available, but '.NET Framework 3.5 (includes .NET 2.0 and 3.0)' has been removed.
However, the files are still on the DVD, you can use:
dism /online /enable-feature /featurename:NetFX3 /source:D:\sources\sxs /all /LimitAccess
or the PowerShell 'Add-WindowsFeature' commandlet to install it:
Add-WindowsFeature –name NET-Framework-Core -source D:\sources\sxs
Edit: On Server 2012 R2 with Update 1 installed (KB2919355) this doesn't work if you are using the original DVD/ISO. You need a DVD or ISO which includes that update. For new installations, install .NET 3.5 before you apply KB2919355.
Best Answer
I was looking for the same answer, and I found this. Maybe this would help:
To install Identity Management for UNIX components
Open Server Manager. To open Server Manager, click Start , point to Administrative Tools , and then click Server Manager.
In the tree pane, expand Roles.
On the role home page for AD DS, in the Roles section, in the list of common tasks, click Add Role Services.
On the Select Role Services page of the Add Role Services Wizard, select the Identity Management for UNIX role services that you want to install, and then click Next.
If the wizard prompts you to install any other role services that are required by Identity Management for UNIX components, click Yes.
After verifying your selections on the Confirm Installation Selections page, click Install.