About hosting an internal SUS to obtain internal software updates
Client Management Suite for Mac
You can allow Mac client computers direct access to the Apple software update site or host a Software Update Server (SUS) internally.
Symantec recommends that you allow direct client access to the Apple software download site rather than setting up a SUS.
Hosting a SUS is a task for advanced Mac administrators because setup is somewhat complex. Setup requires that you change settings manually on every Mac client. To simplify the process, you can create an image, install it on all Mac computers, and then run scripts to change the settings.
The benefit to hosting a SUS internally is that you download software updates from Apple one time and then distribute software updates over the network. This method is more secure and requires lower bandwidth than having Mac clients download software directly over the Internet.