We have a few thousand PCs and laptops, all on Windows 8.1 The WSUS server and DCs are 2012r2. The problem I am having, even though the group policies all direct clients to http://wsusserver:8530 and I have checked the registry is this:
Clients eventually get updates (from the web) and they finally install. But it takes a few days as our firewall person has throttled Windows updates with a traffic shaper to be 1% of our bandwidth. Don't agree with that low of a number, but it shouldn't be an issue, as the clients all should be coming to the WSUS server. This is really impacting trying to image a lot of PCs quickly.
In the windowsupdate.log on clients, it clearly shows the WSUS server. But it takes 24-48 hours to actually get updates on newly installed PCs. Something isn't right.