I have two DC’s also running as DNS1 and DNS2. DC1 is primary running WSE2008 SP1 32bit and DC2 is running WSE2008 R2 64bit. They are also both setup as global catalogs. Recently I noticed when DC1 goes down (as a reboot) my users can not login and lose internet connection as if they are not “failing over” to DC2 for authentication and using DC2 as secondary dns either. Any ideas???