Here is a request that came up recently:
"When installing SSDT manually it downloads a shell copy of Visual Studio 2017 from the Internet. However, if I get the offline copy of SSDT for VS2017 it does not include the Shell copy of VS2017 so the install fails because no Visual Studio 2017 instance is present. I need this for an internal network installation either via SCCM or wide unattended distribution."
This request makes sense for a lot of large enterprises where internet access may be restricted for security considerations.
Steps to accomplish this:
The overall approach is to download the required files on a computer that does have internet access. Then later use those bits on an internal network to install on multiple computers that do not have internet access.
1. Download SSDT for VS 2017 (standalone installer) see https://docs.microsoft.com/en-us/sql/ssdt/download-sql-server-data-tools-ssdt?view=sql-server-2017
2. Download VS SQL SKU - this is essentially the Visual Studio Shell
3. From a Command Prompt execute the following command on a machine with internet connection so you can download all the bits required for a later use offline. Using the --layout option is the key. For more details, see https://docs.microsoft.com/en-us/visualstudio/install/create-a-network-installation-of-visual-studio
vs_sql.exe --layout c:\vs2017offline --lang en-US
Note: above is for US English only ~1GB of files
Alternatively, if you need ALL languages downloaded you can use this command
vs_sql.exe --layout c:\vs2017offline
Note: all languages files add up to about ~3.9GB
Now, that you have all the necessary bits downloaded you can copy them to a network location or media so you can use them for offline (internal) installation
4. Next, to install offline, run this command which will install VS2017 Shell and SQL Server Data Project
Alternatively, for no-GUI install , you can use
vs_setup.exe --NoWeb --wait --norestart --quiet
5. Execute the /layout option for SSDT to download and extract all the files needed for an offline installation
SSDT-Setup-ENU.exe /layout c:\ssdt_install_bits
6. Run this for an interactive/GUI installation (be sure to select SSIS/SSRS/SSAS)
Alternatively for an unattended installation run
SSDT-Setup-ENU.exe /INSTALLALL[:vsinstances] /passive /log log.txt
Note: SSDT-Setup-ENU.exe /help can be run for detailed command options