.NET Core Windows Server Hosting bundle fails to install with error 0x80072efd

Trying to install the .NET Core Windows Server Hosting bundle (DotNetCore.1.0.5_1.1.2-WindowsHosting.exe) on Windows 2008 R2 fails with

Error 0x80072efd: Process returned error: 0x2efd

• The server in question did not have Internet access (by design).

• Trawling the various logs in %LOCALAPPDATA%\Temp showed this

  Error 0x80072efd: Failed to send request to URL: https://download.microsoft.com/download/1/F/0/1F01DD22-748C-41A7-89DE-54D64355CDA6/vc_redist.x64.exe, trying to process HTTP status code anyway.

• Downloaded the package manually and installed

• Retried the original installer and it worked