Overview
Intro
I have mostly found myself needing to do this when prepping to install SQL server on a machine where WSUS is for some reason refusing to serve DotNet 3.5 which at this point is an on-demand feature rather than a standalone installer.
Scripts
To Bypass WSUS
This sets a registry value which allows windows to skip trying to contact the WSUS server.
Set-ItemProperty -Path HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU -Name UseWUServer -Value 0
To Reenable WSUS
And this reverses the value change to resume directing Windows Update to poll the WSUS server. If you group policy is set to enforce this then you can simply leave this step off if desired as it should be corrected on the next consistency check.
Set-ItemProperty -Path HKLM:\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU -Name UseWUServer -Value 1