Good or bad news, Visual Studio no longer comes with ISO file for download in MSDN. You need to run the command in command prompt to get your own Offline Installer.
The instruction link is below.
There are some tricks you may want to be aware of.
1. When you download the exe file from MSDN the file name for Enterprise Version is called mu_visual_studio_enterprise_2017_x86_x64_10049783.exe so do not type vs_enterprise.exe.
2. Do not put you exe in vs2017offline folder. Put it somewhere else.
3. mu_visual_studio_enterprise_2017_x86_x64_10049783.exe –layout C:\VS2017Offline will be enough. You do not need –-lang en-US if you want the language to be English.
You will then see the packages are download like below.
4. You will see character in Red if there is any error.
5. You need a pretty fast Internet.
Like the one below is not yet completed.
6. The complete size of the offline file command that I issued actually will download 23.8 GB.