My CAD_Tower #1 (RIP) ran mostly off-line. I un-plugged the CAT-cable and disabled Norton's between up-dates, used a USB link widget to secured-but-slow Browser_PC for buys & freebies. Current CAD_Tower #2 has more 'cores', and Norton's is either less greedy or hides better from 'Task Manager', so stays 'live'.

Could you allow a small ( weekly ??) window to wake fire-wall, connect CAT-cable and go on-line ? As you would for a Windows update ?? 

FWIW, I found it was much cheaper and more future-resistant to build a stand-alone network-render 'Box' than significantly upgrade either of my Tower #2's twin GPU cards. Please, may we have a dedicated network-render forum ? Rather than related posts scattered hither & yon ??