I’m new to Active directory and just started to study it. :) Some one can explain what happen if Global Catalog server down. What will be impact for? Users those are already logged in on systems and working. Users those are going to login on regular system (Profile already available to that system). Any user who is login to a computer first time. And what are other impacts to domin environment? Dose it make any difference if we talk about 2000/2003/2008?