@Kovach the full OS installers are hosted in on the Apple Store
So nothing to do with SUS.
Does that only apply to OS X Upgrade Files?!
because in the past, when my internal SUS did not haddownloaded new Files yet -
like iTunes, Security Patches - they did not come up in "Updates" within the App Store on the Client Macs.
@H3144-IT The OS X installers like for EL Capitan (and Yosemite before that, Mavericks before that and so on) are actually .app files, not .pkg installers. Generally speaking, SUS dishes out .pkg or package installers (not counting items like XProtect updates). The [Mac] App Store deals with apps. So yes, items like an iTunes update or even a point release OS update will show up on your SUS since those are packages, but full OS X installers will not because they are application installers.
@Kovach The best (maybe the only) way to block El Cap that I've found is to use the Restricted Software process. I've brought this up with our SE in the past and I don't think they have much sympathy.
Thanks @* for the replies. Restricted Software it is!