what happens until CIS is loaded?

when i use a computer with an internet connection which isnt started manually, what happens while bootup until CIS was fully loaded?
Does CIS filter or block connections before its ready? its the last thing that appears in my taskbar. but its the one thing that should work first.

CIS loads its protection modules first in the background before anything else gets loaded. You are fully protected. What you see loading is the GUI only.