We have domain controllers at most sites all around the world. When I open Active Directory Users and Computers at most locations or on servers, it connects to the local DC. Client logins also mostly connecting to local DC's too.
However, sometimes servers and clients, for some reason unknown, connect/authenticate against DC's which are located elsewhere around the world. I can tell with the client when login is really slow and login script shows the DC. I can tell on servers for the obvious reason that it shows the DC hostname on the top, and also is really slow to work with.
Any ideas why some machines would do this? It appears to be rare and random, but confusing (???) Are there ways to force a client / server to default to a DC?
Thanks for your time and any insight!