Thanks for posting in Q&A platform.
The Server Message Block (SMB) protocol is a network file sharing protocol that allows applications on a computer to read and write to files and to request services from server programs in a computer network. So when related to read and write to files from one machine to the remote machine, it will request SMB protocol. It's hard for us to list which service will use SMB protocol.
I would also suggest you could collect network traffic to find out which specific service requires SMB protocol. Meanwhile, I would suggest you could disable SMB protocol temporarily to test which service will not work well.
How many OS services use the SMB protocol? WINS, ADDS, etc? Is there any documentation that list all?
Unfortunately, there is no such an official document talking about this.
Does the ADDS service uses it when processing GPOs for users or computers during logon or startup?
I tested in my lab and find that when processing GPO, it will use SMB protocol.
For logon and startup processes, it will not use SMB protocol.
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