WSUS server configuration

Question

Hi Team,
Please give a guide line on Windows server update service that we are planning to move on another server (Windows server2012). currently this service is installed on windows 2008, now we are planning to move this service to another new server with 2012 os.
The issue is, 
when I check client machines there are a lot of patches are missing, by changing this server i want to confirm all the client machines's security patches are up to date. how do i can achieve this  ? if i configure a new server and if i push all security
patches to client machine,what will happen in client machines installed patches ? is it overwrite ?

Answer 1

The client machine has WUAgent running on the client, and WUAgent (when configured correctly) will contact your WSUS to perform scan/detect, and compare the "current state" of the client machine, with the products+classifications+approvals
on your WSUS.
This doesn't change, if you reconfigure the client to another WSUS, i.e., the WUAgent will perform the same comparison to the "new" WSUS.
e.g., If the client machine already has KB1234567 installed, the client machine will not reinstall that KB1234567 on the client machine.
e.g., If the client machine is "missing + requires" KB1234567, and your new WSUS does have that product+classification+approval, the client machine will download and install KB1234567, according to your configured settings.
Or, do I misunderstand your question?
Don
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