官方：
Applies To: Windows 8, Windows 8.1
For a Windows Server® 2012 core installation that is not connected to the Internet, you can use Windows PowerShell to add .NET Framework 3.5 and provide access to the \sources\sxs folder on the installation media. The \sources\sxs folder can be copied to network share (for example, \\network\share\sxs) to make it easily accessible to multiple computers. The target computer account DOMAIN\SERVERNAME$ must have at least read access to the network share.
Requirements
- Windows Server 2012
- Installation media
- Administrator user rights. The current user must be a member of the local Administrators group to add or remove Windows features.
- Target Computers might need network access and rights to use either alternate sources or an Internet connection to use Windows Update.
Steps
- Start Windows PowerShell in the Administrator Command Prompt by typing:
Copy
powershell
- To install .NET Framework 3.5 from installation media located on a network share, use the following command:
Copy
Install-WindowsFeature Net-Framework-Core -source \\network\share\sxs
Where \\network\share\sxs is the location of the source files.
For more information about the Install-WindowsFeature cmdlet, see Install-WindowsFeature. - To verify installation, run the following command:
Copy
Get-WindowsFeature
The Install State column should show Installed for the .NET Framework 3.5 (includes .NET 2.0 and 3.0) feature.
民间：
Windows Server 2012 有內含 .NET Framework 3.5，供需要向後相容的環境的管理人員來安裝，而 Windows Server 2012 預設在找不到安裝來源時，就會上網連到 Windows Update 下載，問題來了，若剛好環境中沒有網路呢？很簡單，當場死給你看：
你一定覺得很奇怪，為什麼它不給安裝？明明在光碟內有東西啊 (Windows Server 2012 的安裝光碟己經掛起來了)，為什麼還是有這種怪訊息？問題就出在 Windows Server 2012 的安裝檔都封裝在 Install.wim 檔案內，但唯獨 .NET Framework 3.5 不是，我們只能使用替代方案：
這個替代方案的說明還寫得很文言文 ... 不過指出了 .NET Framework 3.5 的檔案在哪裡，只要把路徑設成 [Windows Server 安装盘的位置]:\Sources\SxS，就可以完成安裝了 …